Congressional Testimony of Jay Gulledge - Examining the "Hockey Stick" Controversy



July 27, 2006

At the U.S. House of Representatives Committee on Energy and Commerce, Subcommittee on Oversight and Investigations Hearing: Questions Surrounding the ‘Hockey Stick’ Temperature Studies: Implications for Climate Change Assessments

Examining the "Hockey Stick" Controversy

View slides related to this testimony (pdf).

Mr. Chairman, Ranking Member, and Members of the Committee:

Thank you for the opportunity to speak today. I am Jay Gulledge, Ph.D., Senior Research Fellow for Science and Impacts at the Pew Center on Global Climate Change. I am also an Adjunct Assistant Professor at the University of Louisville, which houses my academic research program on carbon cycling.

The Pew Center on Global Climate Change is a non-profit, non-partisan and independent organization dedicated to providing credible information, straight answers and innovative solutions in the effort to address global climate change. In our eight years of existence, we have published almost seventy reports by experts in climate science, economics, policy and solutions, all of which have been peer-reviewed and reviewed as well by the companies with which we work.

Forty-one major companies sit on the Pew Center’s Business Environmental Leadership Council, spanning a range of sectors, including oil and gas (BP, Shell), transportation (Boeing, Toyota), utilities (PG&E, Duke Energy, Entergy), high technology (IBM, Intel, HP), diversified manufacturing (GE, United Technologies), and chemicals (DuPont, Rohm and Haas). Collectively, the 41 companies represent two trillion dollars in market capitalization and three million employees. The members of the Council work with the Pew Center to educate the public on the risks, challenges and solutions to climate change.

If you take nothing else from my testimony, please take these three points:

1. The scientific evidence of significant human influence on climate is strong and would in no way be weakened if there were no Mann hockey stick.

2. The scientific debate over the Medieval Warm Period (MWP) has been gradually evolving for at least 20 years. The results of the Mann hockey stick simply reflect the gradual development of thought on the issue over time.

3. The impact of the McIntyre and McKitrick critique on the original Mann paper, after being scrutinized by the National Academy of Science, the Wegman panel and a number of meticulous individual research groups, is essentially nil with regard to the conclusions of the Mann paper and the 2001 IPCC assessment.

The science of climate change is an extraordinary example of a theory-driven, data-rich scientific paradigm, the likes of which, arguably, has not occurred since the development of quantum mechanics in the first half of the twentieth century. The product of this strong scientific framework is a body of strong, multifaceted evidence that man-made greenhouse gases are causing contemporary global warming, and that this warming trend is inducing large-scale changes in global climate. The primary evidence is based on physical principles and observational and experimental analysis of contemporary climate dynamics, as opposed to analyses of past climates, which are the subject of this hearing. We can now say with confidence that the evidence of human influence on climate is strong, as described by Dr. Cicerone.

Although paleoclimatology – the study of ancient climates – is an important part of the climate science framework, reconstructions of temperature over the past millennium play a secondary, expendable role in the larger body of evidence, as stated in the recent NAS report titled, Surface Temperature Reconstructions for the Last 2,000 Years: “Surface temperature reconstructions are consistent with other evidence of global climate change and can be considered as additional supporting evidence” (National Research Council 2006, p. 23; hereafter referred to as the NAS report). Dispensing with such reconstructions entirely or proving them fundamentally flawed would have little, if any, impact on our understanding of contemporary climate change. This statement does not imply that millennial climate reconstructions are unimportant, but their main influence will be in the future, when their potential to reveal how climate varied across the earth’s surface from year-to-year in the past (i.e. an annual record of spatially explicit climate dynamics) is fully realized. At that point, such reconstructions will be used in a manner parallel to thermometer records today. This capability would contribute significantly to resolving the current genuine debate in climate science, which is not about whether humans are changing the climate—a point over which there is no scientific controversy—but is about how much human influences will change the climate in the future as a result of greenhouse gas accumulation and other forcings we apply to the climate system. In other words, the goal of spatially explicit paleoclimate reconstructions is to help climatologists determine how physical forcings, such as solar radiation, volcanic eruptions, land-use changes, and changes in atmospheric greenhouse gases, have affected the planet in the past, so that we can improve estimates of how they will do so in the future.

The early MBH reconstructions (Mann et al. 1998; Mann et al. 1999; hereafter referred to as MBH98 or MBH99 or, collectively, MBH) were the first to offer spatially explicit climate reconstructions and therefore represented a breakthrough in climate change science that continues to develop and promises to further our understanding of climate physics in the future. The Wegman report’s conclusion that paleoclimatology “does not provide insight and understanding of the physical mechanisms of climate change” (p. 52), fails to appreciate that the purpose of Dr. Mann’s research is to improve our knowledge of physical mechanisms of climate change by examining how they operated in the past.

Turning our attention to the methodological issues this hearing seeks to investigate, in my opinion, the Wegman report failed to accomplish its primary objective, which was “to reproduce the results of [McIntyre & McKitrick] in order to determine whether their criticisms are valid and have merit” (p. 7). Although the panel reproduced MM's work—verbatim—it only partially assessed the validity, and did not at all assess the merits, of the criticisms directed toward the MBH reconstructions. For instance, MM (McIntyre and McKitrick 2003; McIntyre and McKitrick 2005; heafter referred to collectively as MM) allege that the so-called MBH “hockey stick” result is biased by methodological errors that undermine the conclusion that the late 20th century was uniquely warm relative to the past 1,000 years. This critique only has merit if, after correcting for the errors pointed out by MM, the resulting reconstruction yields results significantly different from the original result that can no longer support the claim of unusual late 20th century warmth. However, the Wegman Report takes no steps to make such a determination.

Fortunately, a different group, one well qualified both statistically and climatologically to tackle this question of merit, had already performed the task several months before the Wegman Report was released. The study by Wahl & Ammann (In press; hereafter referred to as WA06), was peer-reviewed and accepted for publication in the journal Climatic Change early last spring, and has been publicly available in accepted form since last March ( WahlAmmann_ClimChange2006.html). This study, titled, Robustness of the Mann, Bradley, Hughes Reconstruction of Northern Hemisphere Surface Temperatures: Examination of Criticisms Based on the Nature and Processing of Proxy Climate Evidence, carefully reproduced the MBH98 reconstruction and then used their faithful reproduction to test MM’s suggested corrections. They tested each of the criticisms raised by MM in all of their published papers, including both the peer-reviewed and non-peer-reviewed papers. Given that this report specifically examined MM’s criticisms, including the decentering issue that was the main focus of the Wegman report, it is unfortunate that the Wegman report dismissed it in a footnote (p. 48) as “not to the point.”

WA06 have performed a meticulous and thorough evaluation of MBH98, and the answers that this committee seeks about the MBH reconstructions are to be found within this report. After examining each of MM’s three methodological criticisms, WA06 accepted two of them as valid, and have used them to correct the MBH98 reconstruction. I will now show you what effect these corrections have on the MBH98 reconstruction, and then reconsider the uniqueness of the late 20th-century warming trend in the light of these corrections.

The original MBH98 “hockey stick” is shown as a gray line (Fig. 1). The WA06 reproduction of MBH98 is shown in red (Fig. 1). Except for a couple of minor simplifications, WA06 remained faithful to the original MBH method and retained all of the original MBH data, including the original instrumental temperature series from 1992. They wrote their own computer code to perform the calculations, using the R programming language, as recommended by the MM and the Wegman report, rather than the original Fortran language used by Dr. Mann. As you can see, the two reconstructions are materially the same. This result demonstrates that MBH98 can be reproduced based on information available in the original MBH papers and supplemental information and data available on the Internet.

July 27 2006 Testimony Figure 1

July 27 2006 Testimony Figure 2

With this successful reproduction in hand, WA06 were able to test the effects of each of MM’s criticisms on the outcome of the MBH98 reconstruction. After carefully considering the validity of MM’s three criticisms of MBH’s reconstruction methodology, WA06 agreed that 1) decentering the proxy data prior to Principle Component analysis and 2) including the poorly replicated North American Gaspé tree-ring series from 1400-1449 both affected the MBH results. After correcting for these effects, WA06 obtained the results shown in blue (Fig. 2, left frame). The result is a slightly warmer (0.1 °C) early 15th century, with no other time period affected. MM’s third methodological criticism surrounding the inclusion of the bristlecone/foxtail pine series was rejected for several reasons. The right frame in Fig. 2 illustrates that excluding these series has little effect on the MBH98 reconstruction, except to force it to begin in 1450 instead of 1400, because of lack of a data. Since the exclusion had little effect, and losing these data series would hinder reconstructions of earlier climate, WA06 rejected this criticism.

July 27 2006 Testimony Figure 3

The additional 15th-century warmth revealed by making the valid MM corrections still does not approach the warmth of the late 20th century, so MM’s critique cannot yet be said to have merit. However, the corrected result creates the impression of an upward temperature trend backward in time before 1400, begging the question of what would happen to the Middle Ages in the 1,000-year MBH99 reconstruction if it were also corrected? Answering that question is requisite for determining the merit of MM’s critique of MBH. The original 1,000-year MBH99 reconstruction is shown in blue and the corrected version is shown in red (Fig. 3; Ammann & Wahl, submitted). Carrying the correction back to the full millennium reveals that the largest effects remain in the early 15th century, and both earlier and later periods were less affected. Therefore, there is very little difference between the corrected MBH98 and MBH99 reconstructions and the originals, and the original observation that the late 20th century is uniquely warm in the context of the past 1,000 years is not affected. Hence, the valid methodological caveats that MM pointed out do not undermine the main conclusions of the original MBH papers or the conclusion of the 2001 IPCC assessment.

The scientific debate over the Medieval Warm Period (MWP) has been on the same trajectory for at least 20 years, with early indications that the MWP was not a globally coherent event becoming more solid over time. The MBH99 reconstruction represented an evolutionary step—not a revolutionary change—in this established trajectory. The 1990 IPCC figure that Mr. McIntyre, the Wall Street Journal editorial page, and Dr. Wegman have used in their own assessment of past climate is a cartoon, as stated by Dr. Wegman in his testimony last week. I have confirmed this with a number of individuals who were involved with the 1990 IPCC report or with versions of the schematic that pre-dated the 1990 IPCC report. The schematic is not a plot of data and is inappropriate as a comparison to MBH. The text of the 1990 IPCC report clearly states that the figure is a "schematic diagram" and that “it is still not clear whether all the fluctuations indicated were truly global” (p. 202). Furthermore, only three sources of information were cited and those sources conflicted on whether the Northern Hemisphere was warm or cold: “The late tenth to early thirteenth centuries… appear to have been exceptionally warm in parts of western Europe, Iceland and Greenland… China was, however, cold at this time, but South Japan was warm…” Clearly, this report certainly did not paint a picture of any consensus regarding a Medieval Warm Period as a hemisphere-wide phenomenon and characterizing it as such reveals a fundamental misunderstanding of climate science.

The 1992 and 1995 IPCC reports continued this same trajectory of thought. Four years before MBH99, citing 6 papers—still a very limited number, but twice as many as were cited in 1990—the 1995 report stated:

There are, for this last millennium, two periods which have received special attention, the Medieval Warm Period and the Little Ice Age. These have been interpreted, at times, as period of global warmth and coolness, respectively. Recent studies have re-evaluated the interval commonly known as the Medieval Warm Period to assess the magnitude and geographical extent of any prolonged warm interval between the 9th and 14th centuries… The available evidence is limited (geographically) and is equivocal. …a clearer picture may emerge as more and better calibrated proxy records are produced. However, at this point, it is not yet possible to say whether, at a hemispheric scale, temperatures declined from the 11-12th to the 16-17th century. Nor, therefore, is it possible to conclude that the global temperatures in the Medieval Warm Period were comparable to the warm decades of the late 20th century” (p. 174).

Remember that this was written by a team of climatologists as a consensus statement. The consensus at this time, as in 1990 and 1995, was that there was no strong evidence of a hemisphere-wide MWP.

Continuing the same trajectory, the 2001 IPCC Third Assessment Report examined evidence from 10 cited sources for the MWP. The consensus at this point seemed to be turning to the conclusion that there actually was a generally warm Northern Hemisphere during the Middle Ages, but that it was not a strong, coherent pattern of warming:

It is likely that temperatures were relatively warm in the Northern Hemisphere as a whole during the earlier centuries of the millennium, but it is much less likely that a globally-synchronous, well defined interval of “Medieval warmth” existed, comparable to the near global warmth of the late 20th century… Marked warmth seems to have been confined to Europe and regions neighboring the North Atlantic.

Since the MBH reconstructions were hemisphere-wide, and the MWP probably was not, it should not surprise us that the reconstructions lack a strong MWP (MBH99 does show slightly warmer temperatures in the 9th to 14th centuries than in the 15th to 19th centuries).

All available evidence indicates that the situation during the Middle Ages was fundamentally different that what is happening with climate today, which is a well-documented, globally coherent warming trend that is happening North, South, East, and West; at low latitudes and high latitudes; over land and over—and into—the sea. There are new data, published earlier this year, indicating that the atmosphere above Antarctica has warmed dramatically in recent decades (Turner et al. 2006). There is no large region on Earth where large-scale 20th century warming has not been detected, which simply cannot be said of the MWP.

Wahl and Ammann (2006) have demonstrated that the results of MBH are robust “down in the weeds”:

Our examination does suggest that a slight modification to the original Mann et al. reconstruction is justifiable for the first half of the 15th century (~ +0.05°), which leaves entirely unaltered the primary conclusion of Mann et al. (as well as many other reconstructions) that both the 20th century upward trend and high late-20th century hemispheric surface temperatures are anomalous over at least the last 600 years.

The NAS has affirmed the MBH results are also robust in the bigger picture, as well:

The basic conclusion of MBH99 was that the late 20th century warmth in the Northern Hemisphere was unprecedented during at least the last 1,000 years. This conclusion has subsequently been supported by an array of evidence that includes both additional large-scale surface temperature reconstructions and pronounced changes in a variety of local proxy indicators, such as melting on icecaps and the retreat of glaciers around the world, which in many cases appear to be unprecedented during at least the last 2,000 years. Not all individual proxy records indicate that the recent warmth is unprecedented, although a larger fraction of geographically diverse sites experienced exceptional warmth during the late 20th century than during any other extended period from A.D. 900 onward. (p. 3)

Examination of the IPCC reports through time, as well as the primary scientific literature, reveals why the MBH results are so robust—MBH simply assimilated all the available evidence into a quantitative reconstruction—evidence that had already been evaluated qualitatively as lacking a coherent MWP.

This committee is seeking to know the significance of the criticisms leveled at the MBH reconstruction for climate change assessments. The significance is that these criticisms have resulted in the most thoroughly vetted single climate study in the history of climate change research. Dr. Tom Karl summarized the impact most succinctly in his testimony to this committee last week when he said that he would stand by the IPCC’s original assessment: “If you ask me to give qualifications about the findings in the 2001 report with the same caveat in terms of defining likelihood, I personally would not change anything.” Hence, the impact of the MM critique, after being scrutinized by the NAS, the Wegman panel, and a number of meticulous individual research groups, is essentially nil with regard to the conclusions of MBH and the 2001 IPCC assessment.

Also relevant to this committee's questions about climate change assessments is the revelation that climate scientists do know their business, and that a lack of knowledge of geophysics is a genuine handicap to those who would seek to provide what they deem "independent review.” If the assessment of climate science presented in Mr. McIntyre's presentation to the NAS committee, the Wegman Report, and the WSJ is an example of what can be expected from those who have not conducted climate research, then the investigation launched by this committee has demonstrated clearly that “independent review” by non-climate scientists is an exceedingly ineffective way to make climate change assessments.


Mann, M E, R S Bradley and M K Hughes (1998). "Global-scale temperature patterns and climate forcing over the past six centuries." Nature 392(6678): 779-787.

Mann, M E, R S Bradley and M K Hughes (1999). "Northern hemisphere temperatures during the past millennium: Inferences, uncertainties, and limitations." Geophysical Research Letters 26(6): 759-762.

McIntyre, S and R McKitrick (2003). "Corrections to the Mann et al. (1998) proxy data base and northern hemisphere average temperature series." Energy & Environment 14(6): 751-771.

McIntyre, S and R McKitrick (2005). "Hockey sticks, principal components, and spurious significance." Geophysical Research Letters 32(3).

National Research Council, C O S T R F T L, 000 Years. (2006). "Surface temperature reconstructions for the last 2,000 years." from 11676.html.

Turner, J, T a Lachlan-Cope, S Colwell, et al. (2006). "Significant warming of the Antarctic winter troposphere." Science 311: 1914-1917.

Wahl, E and C Ammann (In press). "Robustness of the Mann, Bradley, Hughes reconstruction of northern hemisphere surface temperatures: Examination of criticisms based on the nature and processing of proxy climate evidence." Climatic Change (accepted).

An Agenda for Climate Action




MARCH 30, 2006

Thank you very much.   It is great to be here at Yale.  I want to open my remarks today with some polling numbers.  And I know what some of you may be thinking.  You’re thinking this is a typical Washington thing to do: talk about polls.  And you’re thinking about how polls really don’t get at the real issues.  And you may be right, particularly in this era of television and internet insta-polls.  

I was watching BBC Television shortly after the death of Slobodan Milosevic and the announcer asked viewers to call in with their opinions on this question: “How will Milosevic’s death affect the future of peace in the Balkans?”   And I thought that’s really a fairly sophisticated question.  Sort of the kind of essay question you might have to respond to here at Yale.  And fairly typical, I imagine, of BBC’s expectations of its audience.

In contrast, if you turn on CNN or FOX or one of the other American cable networks, the questions tend to be of the quick yes or no variety.   Here is an actual CNN online poll I found on the Internet: “Would you consider having microchips implanted in your body?  Yes or no.”  I can only imagine how someone might use these results.   

But seriously, I think we can all learn something from looking at the polling on an issue such as climate change, especially when it reveals a clear divergence between public opinion and what is happening in Washington to address this issue.

Just a couple of weeks ago, a national survey showed that Americans of all political beliefs are not happy with the U.S. government’s leadership (or lack thereof) on the issues of global warming and alternative energy. More than three out of four – including two out of three conservatives – said the federal government is not doing enough on either of these issues. And nearly nine out of ten agreed with the following statement—and I quote: “U.S. leaders should take steps to reduce carbon pollution now and speed up the conversion to renewable energy and other alternatives.”

Nine out of ten people. That’s higher than the proportion of dentists who recommend sugarless gum for their patients who chew gum. Seriously, it is an overwhelming majority of Americans. And they all want to see something done to address the climate issue and to put America on a path to a low-carbon future.

Of course, President Bush and Vice President Cheney say they don’t pay attention to polls – and this is one time when I believe them. Because if they were to pay attention to polls, they would be doing something serious to solve the climate problem. In ever-increasing numbers, Americans recognize that we are facing a potential crisis here, and they are looking to their elected leaders in Washington to shape solutions.

I am here today to talk about what those solutions might entail—and I want to do that by focusing on a comprehensive plan to reduce greenhouse gas emissions in the United States that the Pew Center released in February. But I want to start with a brief look at the science of climate change, as well as what is happening now at both the state level and nationally.

Then I want to reserve the rest of my remarks to talk about the Pew Center’s Agenda – because what is happening right now in this country is clearly not enough.

The Science of Climate Change

So first the science. The polling data I talked about shows a pronounced shift in Americans’ views on the climate issue and what to do about it. And the main reason for this shift is not that people are beginning to notice that it’s getting warmer or that the pond over at the town park just isn’t freezing as much in the winter as it used to.

No, what’s happening is that people are beginning to pay attention to the science on this issue. And they are coming to understand that there is no longer any doubt about it: climate change is a very real and very serious problem.

Scientists now know for certain that the globe has been warming for the past century. They also know that human activities, mainly the burning of coal and oil, but also agriculture and deforestation, have dramatically increased concentrations of heat-trapping gases in the atmosphere

In just the past year, the science linking observed climate change directly to human activities has become increasingly solid. And the impacts of climate change, distributed across the globe, are occurring in patterns that can only be explained by human activities and not by natural variations in regional climate. During the first half of the 20th century, natural factors may have been as important as anthropogenic factors. Unfortunately, the more dramatic warming that has occurred since then has been dominated by the human influence. The science is now clear on this point.

But what is really changing how people view this issue is that the impacts we are seeing now—today—are happening much sooner than anyone might have anticipated even a decade ago. These changes were predicted, but even the scientists who made the predictions are surprised at the rate at which they are now occurring.

What do we know about the impacts of climate change?

We know that ice cover around the world is changing at an unprecedented rate. Just last month, new satellite-based measurements of ice flow in Greenland were published in the Journal Science. And what they showed is that the second largest land-based ice sheet in the world is losing ice twice as fast as scientists had estimated before these new measurements were available. This ice sheet, if completely melted, could raise global sea level by almost 20 feet. That would permanently flood not just New Orleans, but virtually all of America’s major coastal cities.

We also know that we are experiencing a worldwide loss of mountain glaciers, a trend that is accelerating. By mid-century, most mountain glaciers may be gone.

We know that hurricanes are becoming more intense, not just in the Atlantic, which gave us Katrina and Rita, but in all oceans where hurricanes occur.

We know that ecosystems around the world are showing signs of responding to climate change. One study found that 130 species - both plants and animals - have responded to earlier spring warming over the last 30 years. These organisms have changed their timing of flowering, migration and other spring activities. More startling than this, however, climate change is also driving some species to extinction. For instance, in the past 20 years dozens of species of mountain frogs in Central America have disappeared because of a disease that formerly did not occur where they live. Early this year, a paper in the journal Nature revealed that the disease-causing organism, a fungus, has spread to higher elevations as a result of climate warming. This paper not only provides an example of climate change driving species extinct, but also strong scientific evidence that climate change is promoting the spread of diseases to new areas. In the authors' own words, "With climate change promoting infectious disease and eroding biodiversity, the urgency of reducing greenhouse-gas concentrations is now undeniable."

And these are, if I may say this, just the tip of the melting iceberg.

So the bottom line is this: The earth is warming; the impacts—once only predictions—are now upon us and are likely to worsen; and human activity is largely to blame.

U.S. Action on Climate Change

So we have all this science, and we have Americans responding to it by saying that our government needs to do more. How has our government responded? Well, at the state level at least, the response has been encouraging. For example:

Twenty-one states and the District of Columbia have enacted renewable energy mandates requiring utilities to generate a share of their power from renewable sources.

  • Twenty-eight state governments have adopted climate action plans; 15 have programs or policies in place to reduce, sequester or register greenhouse gases; and nine states have statewide targets for reducing their emissions.

Connecticut, I am pleased to say, has done all of these things. And more. As many of you know, Connecticut, along with six other northeastern states has signed onto a regional initiative called RGGI that is aimed at reducing carbon dioxide emissions from power plants in the Northeast. This is the first “cap and trade” program to control these emissions in the United States. It couples a mandatory cap on emissions from the electricity sector with a market-based trading program that will allow companies to achieve their reductions at the lowest possible cost.

So Connecticut is really out in front on this issue—and all of you should be proud to live in a state with leaders who understand the need for climate action.

Among the other states that are taking this issue seriously, I have to mention California.

Like Connecticut, California has established greenhouse gas emissions targets, and they are very ambitious. And that state also has taken steps to begin regulating carbon dioxide emissions from cars and trucks. (a policy that Connecticut will follow if it survives the automakers’ legal challenge)

And then there is New Mexico, a major coal-producing state. NM has established its own targets, and has also announced a partnership with neighboring Arizona to jointly reduce greenhouse gas emissions and address the impacts of climate change in the Southwest.

These are just a few examples of the kinds of things states are doing. Now, you might think one state’s actions cannot possibly affect a global problem like climate change. But consider this: California’s emissions top those of Brazil. Texas comes in ahead of Canada, the UK and Mexico. And Illinois produces more CO2 than the Netherlands. States are a significant part of the climate problem, and many of them, including Connecticut, are showing they can be a significant part of the solution as well.

So what about our national government? To what extent have our leaders in Washington embraced the need for action? Well, I have some good news and some bad news.

First the good news: During the U.S. Senate’s debate on energy legislation last year, senators approved a bipartisan measure calling for a national, mandatory, market-based program to slow, stop and, ultimately, reverse the growth in U.S. greenhouse gas emissions. The legislation was sponsored by senators Domenici and Bingaman, the chair and the ranking Democrat on the Senate Energy Committee. And although it was a nonbinding measure, it marked the first time the Senate has gone on record to support mandatory action on this issue. That is an important achievement – and now Senators Bingaman and Domenici are seeking input on how to create a mandatory climate program that gets real results.

Still in play is the cap and trade legislation proposed by Senators John McCain and Connecticut’s own Joseph Lieberman. And now Senator Dianne Feinstein has joined the issue as well, offering her own version of a cap and trade climate policy. And we are helping others in Congress develop other proposals. So clearly, we’ve seen an up-tick in Congressional interest in this issue. Granted, these proposals may not become law right away, probably not before 2008, but I believe it is only a matter of time before limits on greenhouse gas emissions are in place.

So that’s the good news: people on Capitol Hill, especially in the Senate, are looking at this issue and thinking hard about how to address it.

The bad news is that the White House and leadership of the House of Representatives are strongly opposed to addressing climate change in any significant way. As a result, I do not believe anything substantive is likely to come out of Congress on this issue for some time. I would like to be proved wrong, but it is hard for me to see any leadership on this issue coming from the White House during the remainder of its term.

Despite the President’s famous statement in his State of the Union Address that America is addicted to oil, Washington does not seem truly ready to fight the addiction. The Administration’s budget proposals don’t come anywhere close to providing the shot in the arm we need to accelerate clean energy research in this country. (Again, this is despite the American public’s clear interest in alternative energy solutions.) More importantly, even if the technology programs were properly funded, they simply are not enough.

And this is the problem with what has been happening on this issue to date, whether at the state or the federal level. In addition to being late to start, what we are talking about and doing is simply not enough. As I said, I applaud what many of the states are doing, and I am pleased to see members of Congress beginning to understand the need for action. But we need to remember what this is about.

James Hansen, the NASA scientist who is one of the world’s leading experts on climate change, says we have just 10 years to begin reducing greenhouse gases before global warming reaches what he calls a tipping point; the tipping point, as the phrase implies, is the point from which we may not be able to avert a catastrophe. To forestall a climate crisis, we must stabilize greenhouse gas concentrations in the atmosphere. And what does that mean? According to the Intergovernmental Panel on Climate Change, it means limiting the concentrations to about 550 parts per million –roughly double the pre-industrial level of atmospheric greenhouse gases.

To get to that level, we need to reduce global CO2 emissions by 55 to 85 percent below what is currently projected. Fifty-five to 85 percent. And we need to do this at the same time that energy demand around the world is growing at an unprecedented rate. We need to act now to come up with ways to limit emissions growth without endangering economic growth. And make no mistake: The United States, which is responsible for one-fourth of global emissions, needs to play a leadership role.

And that is going to require a fundamental shift. We need to move from an economy based on traditional burning of fossil fuels to one based on more energy efficiency; increased use of low-carbon energy sources; and the capture and storage of carbon from fossil fuels. This is not something that one piece of legislation, or even one strategy or one approach, will accomplish. We need a comprehensive approach.

An Agenda for Climate Action

In February, the Pew Center released the first comprehensive plan to reduce greenhouse gas emissions in the United States. Our Agenda outlines an ambitious yet practical approach to addressing this issue. It is based on seven years of Pew Center analysis and work with leading businesses and policymakers.

The number-one lesson we have learned from this work: There is no single technology fix, no single policy and no single sector that can solve this problem on its own. For example, addressing emissions from the utility sector is key, but doing only that leaves out about 60 percent of emissions. In the same way, if we adopt policies to limit emissions from transportation and do nothing else, we’re hitting just 30 percent of the problem—which is significant, of course, but it is not enough.

The Pew Center’s Agenda outlines 15 specific recommendations in six overarching areas where the United States must take action. These six areas are: 1) science and technology; 2) market-based programs; 3) sectoral emissions; 4) energy production and use; 5) adaptation; and 6) international engagement.

I want to provide you with a better sense of what our Agenda is about by highlighting some of the recommendations in each of these six areas.

In the area of science and technology research, we call for increased and stable funding to spur technological innovation. Because it is important to spend this money wisely, we suggest the use of a “reverse auction.” Unlike a traditional auction, where buyers bid against each other to purchase an item, a reverse auction allows providers of goods or services—in this case, new, climate-friendly technologies—to compete for a pot of money by offering emissions reductions.

Since 1998, California has used reverse auctions to promote development of renewable energy. The program collects money through a charge on electric power, and solicits bids for renewable projects, with the money going to the bidder that can provide the renewable energy at the cheapest rate. Thus far, there have been 81 successful bids to produce renewable energy through this competitive and cost-effective system.

Second, we believe it is critically important to enact a mandatory cap and trade program that applies to large stationary sources – power-plants and major manufacturing facilities. Our work over the years has shown that market mechanisms such as emissions trading allow companies to reduce emissions in the cheapest, most efficient manner possible.

What a cap and trade system does in essence is send a signal to the market. It tells the market that there is a value in reducing emissions. And it tells inventors and investors that there is profit in creating and deploying climate-friendly technologies. It creates an essential pull for new technologies to enter the market. The push for those technologies, in turn, comes from the funding of innovation, through mechanisms like the reverse auction. And we need both the push and the pull to achieve real and cost-effective results. A cap and trade system coupled with a reverse auction is a great example of a comprehensive approach.

But the fact is that a cap-and-trade system by itself, and particularly at the level that would be politically practical, is not enough. In fact, many of the current proposals for cap-and-trade programs, tend to leave out the transportation sector, which is of course a major source of emissions.

And this is why the Pew Center’s Agenda also calls for sectoral approaches such as transforming the much-maligned Corporate Average Fuel Efficiency (or CAFE) program. CAFE, as you know, sets average fuel efficiency levels for carmakers across their fleets. But the standards have not changed significantly in over 20 years. And, because SUVs and light trucks now make up as much as half of the new-vehicle product mix, the average fuel economy of all the cars and light trucks sold in America—import and domestic— is no better today than it was in the early 1980s. Although NHTSA is currently considering changing the way it classifies different kinds of light trucks, it is unclear what that will translate into as far as actual emission reductions. But I am fairly sure it won’t be enough.

We recommend strengthening and converting the United States’ current fuel economy standards to a set of tradable standards based on greenhouse gas emissions. If you are looking to protect the climate, focusing on emissions rather than fuel efficiency seems more logical. By creating a market for emissions reductions through trading, and at the same time supporting the development of low-emission vehicles and fuels (the push and pull approach)—you can reduce the cost of getting the job done.

Of course, it is not only in the transportation sector where additional action is needed.

Our plan proposes tighter standards for appliance and equipment efficiency, as well as incentives for the manufacture of more climate-friendly products. Similarly, for the building sector, we call for stricter building codes to decrease energy use. We even touch on the role of the agriculture and forestry sectors in keeping carbon out of the atmosphere through climate-friendly practices. Again, all sectors of the economy have a role to play in this, and it is going to take all sectors to achieve the results we need.

But all sectors are not equal when it comes to having a hand in the climate problem and its potential solutions. One sector stands head and shoulders above the rest, and that is, you guessed it, energy. Eighty-percent of US greenhouse gas emissions come from the combustion of fossil fuels. The ways in which we generate, distribute and use energy have a profound impact on our emissions of greenhouse gases—and that is why the Pew Center’s Agenda reserves a special set of recommendations for this all-important sector. Our recommendations cover all of the major energy sources.

Let’s start with coal. And we need to be realists here. Coal is responsible for 50 percent of our nation’s electricity. It is cheap and it is plentiful and I believe (along with many others) that it will continue to play a role in meeting U.S. and global energy needs for years to come. Let’s look for a moment at our current and projected energy mix and needs. If we assume coal will continue to contribute roughly half of U.S. electricity requirements; and you look at the projected growth of energy demand in this country - by 2025 the U.S. will need to grow our coal capacity by 60% - that would mean emissions from U.S. coal burning alone in 2025 would equal 15% of our current global emissions. Globally, the numbers are even more dramatic. China is even more dependent on coal for electricity than the US. It contributes to 75% of their electricity needs, and despite efforts to ramp up generation in gas, renewables and nuclear, the overall share of coal in the mix is unlikely to change significantly. Think about this: China is building new coal power plants at a rate of one plant per week.

So we need to get serious—and I mean very serious—about reducing emissions from coal-fired power plants. First, we need to build the very best, most efficient coal burning power plants possible to reduce emissions per kWh of electricity. And then we have to prove that the carbon dioxide that still is emitted from these plants can be captured and stored (sequestered) in geological formations where it can be kept from entering the atmosphere for centuries or millennia.

We recommend an aggressive program of research, development and demonstration for these technologies. A few random demonstration projects done at a leisurely pace clearly are not enough. We need to build the most efficient plants and we need a concerted public-private effort to demonstrate that capture and sequestration can work, and then we have to insist that it be done.

But dealing with coal alone is not enough. Because capture and storage technologies are not quite ready, we need to work on expanding the role that renewables play in our energy future. We should also concentrate on expanding natural gas supplies and using natural gas more efficiently. And we will need to solve the problems associated with nuclear power. For each energy source, we propose specific measures in areas from R&D to incentives to regulation that can help expand the suite of carbon-friendly technologies that are necessary to put us on a low-carbon path.

It is of course important to understand that none of the things I have talked about can fully prevent all of the potential effects of climate change. In fact, as I mentioned at the start of my remarks, many impacts are already being seen. This is why, at the same time that we are working to reduce emissions in order to minimize the effects of climate change, we also need to develop a national strategy to adapt to those effects. Climate change is happening, and it is going to affect everything from agriculture to public safety and public health. Without a strategy, as well as a system for identifying the early warning signs of climate problems confronting our country, we are going to be caught unprepared.

Finally, the Pew Center’s Agenda, while primarily focused on domestic actions, also calls for greater U.S. participation in international negotiations on this issue. It is obvious now that there is no chance the United States will sign on to the Kyoto Protocol. Kyoto, of course, is the 1997 agreement that sets country-by-country targets for reducing emissions for industrialized countries. However you feel about Kyoto, the fact remains that climate change is a global problem that demands a global solution. It also needs a longer-term solution; Kyoto includes targets only through 2012.

We need to engage every country that is a major source of these emissions, not just the United States but China and India as well. And we need to come up with ways to make the process fair and equitable for all involved.

Finding common ground on global approaches to the climate problem has been the focus of a special Pew Center initiative we launched a couple of years ago and released in Montreal in December. I don’t want to spend a lot of time on it here, but we organized a dialogue-with business and political leaders from the United States, the United Kingdom, Germany, Japan, Australia, China, India, Mexico, Brazil, and other countries. And a key take-away from the group is that we need a more flexible framework than Kyoto, something that allows different countries to take on different types of commitments, all under the umbrella of a common global framework.

Working with us on global approaches are Senators Lugar and Biden, the majority and minority leaders in the Senate Foreign Relations Committee. And I cannot speak highly enough of what these Senators have done. They sent senior staff to participate in our dialogue. They co-sponsored a resolution urging US leadership in the international negotiating process, and are committed to getting a majority of Senators to support it this year. And they expect to hold hearings this year on energy security and climate change.

So those are the recommendations in the Pew Center’s Agenda. Once again, they cover the areas of: 1) science and technology; 2) market-based programs; 3) sectoral emissions; 4) energy production and use; 5) adaptation; and 6) international engagement.

The Role of Business

What I want to emphasize about this agenda is that this isn’t pie-in-the-sky thinking. All of the steps we are recommending are eminently doable. We just need the political will to do them.

And, if we do these things thoughtfully, this transition can actually become a platform for new economic growth, new jobs, new manufacturing and service industries, and new roles for sectors such as agriculture and forestry in our nation’s efforts to protect the climate.

America’s business leaders appear to understand this. They know that a mandatory program to limit and reduce greenhouse gas emissions in the U.S. is inevitable, and they know it is in their best interests to see that the program is designed intelligently and fairly.

That’s why so many of them stood with us at the event in February where we unveiled our Agenda. And why so many companies responded to Senator Bingaman and Domenici’s call for proposals and suggestions to fashion legislation setting mandatory caps on U.S. emissions of greenhouse gases. And that is why last June, five Fortune 500 companies provided testimony on climate to the Science Committee of the House of Representatives. ;

There are two unifying themes in these examples of corporate and investor leadership. First, most corporate leaders know that greenhouse gas regulation is inevitable. Second, they know that properly designed mandatory climate policies are consistent with sound business planning and good corporate governance. As more companies and investors come to this realization, pressure will mount for other companies to take a more responsible stance on the climate issue. And as corporate leadership aligns with activity at the state and international level, pressure will grow for serious policy change at the federal level.

Why? Because these companies want to ensure that the burden of responding to the climate problem is evenly shared across all sectors of the economy. And they also want another thing: they want certainty. Businesses, particularly electric utilities that have to make significant up-front investments in power plants, are saying they need to be able to plan for the future-and they cannot plan effectively without knowing what kind of policies this country is going to adopt to control emissions.

I opened my remarks with some polling data that shows Americans clearly understand the need for action on this issue. And I have concluded with examples of how business leaders, too, are concerned and how they’re beginning to take action. And, when you consider what many of the states are doing to address this issue, you realize that the one place where climate change still hasn’t achieved priority status is in Washington. Yes, we have seen a fair amount of discussion of this issue. And, yes, there are policymakers who take it seriously and who want to shape solutions.

But we need solutions now. We don’t have time to wait. Climate change policy in this country is at a crossroads, and the American public, together with visionary business and state leaders, are pointing us in the direction we need to go.

The sooner we get started by reversing our current course and adopting a serious and comprehensive approach to addressing this problem, the better off and the safer we will be. And the sooner we’ll begin transforming our economy for the realities and the opportunities that lie ahead.

And so, I will leave you today with another bit of polling described by Jay Leno. "According to a survey in this week’s Time magazine, 85% of Americans think global warming is happening. The other 15%" according to Leno, "work for the White House." Thank you very much. I welcome your questions.

Agenda for Climate Action


 Agenda for Climate Action cover

Agenda for Climate Action

Prepared by the Pew Center on Global Climate Change
February 2006

Press Release

Download report (pdf)

Download a brochure summarizing the report (pdf)


Eileen Claussen, President, Pew Center on Global Climate Change

Over the past seven years, the Pew Center has published more than 60 reports on the science, economics, solutions, and policy options related to global climate change. Over that time, the scientific consensus on this issue has only strengthened, but there is, as yet, no consensus on the appropriate portfolio of policies that are required to address global climate change successfully. This Agenda for Climate Action is C2ES’s attempt to fill that gap. It takes a comprehensive look at a suite of climate, energy, and technology policies that could provide meaningful reductions in greenhouse gas emissions throughout the economy.

This report finds six areas in which the U.S. must take action: (I) science and technology research, (II) market-based emissions management, (III) emissions reductions in key sectors, (IV) energy production and use, (V) adaptation, and (VI) international engagement. In the areas of science and technology research, we call for increased stable funding for both, along with innovative approaches to distribute funds efficiently. We propose a mandatory GHG reporting system, which can form the basis for tracking voluntary reductions, accompanied by a large-source, economy-wide cap-and-trade program for greenhouse gases. This combination of technology investment and market development will provide for the most cost-effective reductions in greenhouse gases, as well as create a market for GHG-reducing technologies.

While these broader efforts are critical, sector-specific actions are also needed. To address emissions from the transportation sector, we propose converting the struggling Corporate Average Fuel Economy (CAFE) program into a more ambitious but tradable GHG standard, along with increased support for low-emission vehicles and fuels. For the industrial sector, we encourage greater outreach and incentives for improvements in process efficiency and the manufacture of low-GHG products. In the agriculture sector, biological sequestration programs in Farm Bill legislation must receive proper funding and prioritization. Because energy is at the heart of this issue, we tackle this sector separately, making recommendations for each major energy source. To enable continued use of coal in a climate-friendly manner, we promote aggressive research and development on carbon separation and capture technologies, development of a regulatory framework for geologic sequestration, and advanced generation coal plants. Natural gas is an important transition fuel, and we support the expansion of natural gas transportation infrastructure and production. We propose extending incentives for renewable fuels and electricity generation, an increased focus on biomass, and federal-level support for renewable credit-trading programs. We also support continued use of nuclear power generation, pending resolution of issues such as safety and waste storage. There are vast opportunities for improving efficiency on an economy-wide basis, so we promote improved efficiency in electricity production (through distributed generation, combined heat and power technologies), in electricity transmission (through test beds for an advanced grid), and during energy use (through building codes, product standards, and manufacturing process improvements).

Because none of these efforts will fully prevent all potential effects of climate change (indeed, many impacts are already being observed), we propose the development of a national adaptation strategy and the funding of early warning systems. Last but not least, while the Agenda focuses on domestic actions, it argues for greater participation by the U.S. in international negotiations to engage all major emitters in a global solution.

Despite the specificity of many of the steps included here, there is still much room for ongoing refinement and elaboration of these recommendations. While we have consulted with many stakeholders in the development of this report, we look forward to building upon the suggestions described here through further outreach and consultation.

This report follows the publication of International Climate Efforts Beyond 2012: Report of the Climate Dialogue at Pocantico, an examination of options for advancing the international climate effort post-2012. Taken together, these two documents offer a promising path forward for the U.S. and the world in tackling global climate change.

Executive Summary

Climate change is one of the most complex issues that the world will face in this century. Concentrations of greenhouse gases in the atmosphere have already reached levels unprecedented for hundreds of thousands of years, causing changes not only in global temperature, but also in observable impacts throughout the world, and these changes are happening more quickly than expected.  The broad consensus of established scientific experts both internationally and domestically is that most of the warming in recent decades can be attributed to human activities.  In addition, the rate and severity of these changes will increase without significant steps to reduce greenhouse gas emissions (GHGs).  Stabilizing greenhouse gas concentrations will require a fundamental shift in our energy system, but this transition will have other benefits as well, including improved competitiveness, security, air quality, public health, and job creation. This transition will not be easy, but it is crucial to begin now. 

This Agenda is the Pew Center's attempt to develop and articulate a responsible course of action for addressing climate change.  It identifies fifteen actions that should be started now, including U.S. domestic reductions and engagement in the international negotiation process.  It includes both broad and specific policies, combining recommendations on technology development, scientific research, energy supply, economy-wide markets, and adaptation with critical steps that can be taken in key sectors. While reductions across sectors and sources of emissions are key, these steps are not likely to happen simultaneously, nor without costs.  However, these recommendations have been designed to be both cost-effective and comprehensive.


Invest in science and technology research.

1. Ensure a robust research program though the Climate Change Science Program.

2. Offer long-term, stable funds—in the form of a reverse auction—to GHG-related technology research and development.

Establish mandatory limits on greenhouse gas emissions and harness market mechanisms for economy-wide reductions.

3. Create a mandatory GHG reporting system as a basis for an economy-wide emissions trading program.

4. Implement a large-source, economy-wide cap-and-trade program for greenhouse gases.

Stimulate innovation across key economic sectors.

5. Transportation: Convert the Corporate Average Fuel Economy (CAFE) program into strengthened, tradable corporate average emissions standards. Support biofuels, hydrogen, and other low-GHG fuel alternatives.

6. Manufacturing: Provide outreach and incentives to manufacturers for improvements in industrial efficiency and low-GHG technologies, and support the production of low-GHG products.

7. Agriculture: Raise the priority and funding levels for Farm Bill programs and other federal initiatives on carbon sequestration.

Drive the energy system toward greater efficiency, lower-carbon fuels and carbon capture technologies.

8. Coal and Carbon Sequestration: Provide funding for tests of geologic carbon sequestration and for research, development and demonstration (RD&D) projects on separation and capture technologies, in combination with advanced generation coal plants. Establish an appropriate regulatory framework for carbon storage.

9. Natural Gas: Expand natural gas transportation infrastructure and production.

10. Renewables: Significantly “ramp up” renewables for electricity and fuels, including an extension and expansion of the production tax credit, a uniform system for tracking renewable energy credits, and increased emphasis on biomass.

11. Nuclear Power: Provide opportunities for nuclear power to play a continuing role in a future low-carbon electricity sector.

12. Efficient Energy Production and Distribution: Support the development and use of combined heat and power installations, distributed generation technologies, and test beds for an upgraded electricity grid.

13. Efficient Energy Usage: Reduce energy consumption through policies that spur efficiency, including appliance and equipment standards, building R&D and codes, and consumer education.

Begin now to adapt to the inevitable consequences of climate change.

14. Develop a national adaptation strategy through the Climate Change Science Program and Climate Change Technology Program, and fund development of early-warning systems for related threats.

Engage in negotiations to strengthen the international climate effort.

15. Review options for a new or modified agreement to ensure fair and timely action by all major emitting countries, and participate in negotiations to establish binding climate commitments consistent with domestic interests.

These fifteen recommendations are not the only means of achieving a lower-carbon future, but taken together, they would chart a climate-friendly path for the U.S.. Putting the Agenda into practice will take political will and policy action. All recommendations require government leadership, private sector commitment and time. Nonetheless, the details of specific recommendations in this Agenda are less critical than the compelling need to get started. Further delay will only make the challenge before us more daunting and costly.

Business Support

Agenda for Climate Action
Report Release
February 8, 2006
National Press Club, Washington, DC

Remarks made by business representatives at the release:

David Hone
Group Climate Change Adviser
Shell International Limited (pdf)

Melissa Lavinson
Director for Federal, Governmental and Regulatory Relations
PG&E Corporation (pdf)

Bill Gerwing
Western Hemisphere Health, Safety, Security, and Environment Director
BP (pdf)

John Stowell
Vice President of Federal Affairs and Environmental Safety
Cinergy (pdf)

Ruksana Mirza
Vice President, Environmental Health and Safety
Holcim (US) Inc. (pdf)

Tom Catania
Vice President, Government Relations
Whirlpool Corporation (pdf)

Supporting statements: Agenda for Climate Action

The Pew Agenda is an example of the kind of big picture, integrated thinking that is needed to tackle the climate issue.  We're pleased that the Agenda makes the point that climate solutions should be market based while covering all parts of the economy and resolving regulatory uncertainty.  These are all vital as the utility industry prepares to build the next generation of power plants needed by our growing economy.

James E. Rogers, Chairman, President, and Chief Executive Officer
Cinergy Corp.

The changes needed in our energy infrastructure to meet future demand and respond to climate change will not happen by chance - a clear, long term framework will give business the necessary incentive and confidence to invest further.

John D. Hofmeister, President and US Country Chair
Shell Oil Company

Holcim is pleased with the leadership that the Pew Center has taken with regard to greenhouse gas reduction policies and the depth of research that comprises the foundation of this report. Importantly, the Pew Center recognizes the necessity of market-based solutions and that various sector needs must be taken into consideration if we are to have consensus in what must be done to contain and ultimately reduce the generation of greenhouse gases.

Patrick Dolberg, President & Chief Executive Officer
Holcim (US) Inc.

Through its association with the Pew Center, Alcan has identified another avenue through which to actively address climate change and its effects on the long-term sustainability of the Company. This report sends a clear message, calling on all stakeholders to broaden their investment in tackling the economic, social, and environmental issues that climate change presents.”

Daniel Gagnier, Senior Vice President, Corporate and External Affairs
Alcan Inc.

Intel supports Pew's efforts to advance the national discussion on climate change by proposing options that merit careful consideration. Intel agrees that climate change is a serious issue, and has been actively working to mitigate its own climate impact through aggressive programs to reduce energy consumption and emissions of global warming compounds.

Dane Parker, General Manager of Environmental Health and Safety


Press Release: Agenda for Climate Action

Press Release
February 8, 2006

Contact: Katie Mandes, (703) 516-0606


All Sectors Must Share in Solution

WASHINGTON, D.C. – The Pew Center on Global Climate Change released the first comprehensive plan to reduce greenhouse gas emissions in the United States.  The Agenda for Climate Action identifies both broad and specific policies, combining recommendations on economy-wide mandatory emissions cuts, technology development, scientific research, energy supply, and adaptation with critical steps that can be taken in key sectors.  The report is the culmination of a two-year effort that articulates a pragmatic course of action across all areas of the economy.  

The report calls for a combination of technology and policy and urges action in six key areas:  (1) science and technology, (2) market-based programs, (3) sectoral emissions, (4) energy production and use, (5) adaptation, and (6) international engagement.  Within these six areas, the Agenda outlines fifteen specific recommendations that should be started now, including U.S. domestic reductions and engagement in the international negotiation process.  All the recommendations are capable of implementation in the near-term. 

The report concludes that there is no single technology fix, no single policy instrument, and no single sector that can solve this problem on its own.  Rather, a combination of technology investment and market development will provide for the most cost-effective reductions in greenhouse gases, and will create a thriving market for GHG-reducing technologies.  To address climate change without placing the burden on any one group, the report urges actions throughout the economy. 

“Some believe the answer to addressing climate change lies in technology incentives.  Others say limiting emissions is the only answer.  We need both,” said Eileen Claussen, President of the Pew Center.

Emissions in the United States continue to rise at an alarming rate.  U.S. carbon dioxide emissions have grown by more than 18% since 1990, and the Department of Energy now projects that they will increase by another 37% by 2030. 

Joining the Pew Center at the announcement were representatives from the energy and manufacturing sectors.  Speaking at the release were:  David Hone, Group Climate Change Adviser, Shell International Limited; Melissa Lavinson, Director, Federal Environmental Affairs and Corporate Responsibility, PG&E Corporation; Bill Gerwing, Western Hemisphere Health, Safety, Security, and Environment Director, BP; John Stowell, Vice President, Environmental Strategy, Federal Affairs and Sustainability, Cinergy Corp., Ruksana Mirza, Vice President, Environmental Affairs, Holcim (US) Inc.; and Tom Catania, Vice President, Government Relations, Whirlpool Corporation.


While actions are needed across all sectors, some steps will have a more significant, far-reaching impact on emissions than others and must be undertaken as soon as possible. 

  • A program to cap emissions from large sources and allow for emissions trading will send a signal to curb releases of greenhouse gases while promoting a market for new technologies.
  • Transportation is responsible for roughly one-third of our greenhouse gas emissions, and this report addresses this sector through tradable emissions standards for vehicles.
  • Because energy is at the core of the climate change problem, the report makes several recommendations in this area: calling for increased efficiency in buildings and products, as well as in electricity generation and distribution.  Incentives and a nationwide platform to track and trade renewable energy credits are recommended to support increased renewable power.  In recognition of the key role that coal plays in U.S. energy supply, the report calls for the capture and sequestration of carbon that results from burning coal. Nuclear power currently provides a substantial amount of non-emitting electricity, and is therefore important to keep in the generation mix. The report recommends support for advanced generation of nuclear power, while noting that issues such as safety and waste disposal must also be addressed.
  • While most of the recommendations focus on mitigation efforts, the report acknowledges that some impacts are inevitable and are already being seen. As a result, it proposes development of a national adaptation strategy to plan for a climate-changing world. 
  • Finally, despite the importance of efforts by individual countries on this issue, climate change cannot be addressed without engagement of the broader international community.  The report recommends that the U.S. participate in international negotiations aimed at curbing global greenhouse gas emissions by all major emitting countries.

Other recommendations include: long-term stable research funding, incentives for low-carbon fuels and consumer products, funding for biological sequestration, expanding the natural gas supply and distribution network, and a mandatory greenhouse gas reporting program that can provide a stepping stone to economy-wide emissions trading. 

The full text of this and other Pew Center reports is available at  


The Pew Center was established in May 1998 by The Pew Charitable Trusts, one of the United States’ largest philanthropies and an influential voice in efforts to improve the quality of the environment.  The Pew Center is an independent, nonprofit, and non-partisan organization dedicated to providing credible information, straight answers, and innovative solutions in the effort to address global climate change.  The Pew Center is led by Eileen Claussen, the former U.S. Assistant Secretary of State for Oceans and International Environmental and Scientific Affairs.

Global Warming Facts and Figures

These facts and figures are divided into five sections:

  1. The Physical Basis of Global Warming
  2. Observed Temperatures and Greenhouse Gas Trends
  3. Impacts
  4. U.S. Emissions
  5. International Emissions

These sections explain the scientific evidence for human impacts on the climate system, specifically global warming.

Each section below contains several figures. Click on the section's heading or image to view all.

The Physical Basis of Global Warming
Observed Temperatures and Greenhouse Gas Trends

U.S. Emissions

International Emissions


Global warming facts and figures to explain the scientific evidence for human impacts on the climate system.

Global CO2 Flows, Carbon Reservoirs, and Reservoir Changes

The figure below portrays estimated sizes of the earth's carbon reservoirs, average annual changes in the amount of carbon held in the reservoirs, and recent flows of CO2 between land and ocean reservoirs and the atmosphere. The size of carbon reservoirs are written in white, while natural processes between these reservoirs appear in yellow.  Additional carbon introduced into the system by humans appears in red. For example, humans release 9 GtC/y but 3GtC/y are taken up by plants and soil carbon and another 2 GtC/y goes into the ocean. The remaining 4GtC/y goes into the atmosphere, increasing CO2 concentrations.

Figure 2: Global CO2 Flows, Carbon Reservoirs, and Reservoir Changes
Note: Tan colored pool is decreasing in size. Blue colored pools are increasing. Intensity of blue indicates magnitude of stock change. Numbers in red indicate estimated total amount of carbon in reservoir. Numbers in green indicate average annual change in amount of carbon in reservoir.
Gigatons (Gt) = 109 metric tons.
Sources: Bolin et al. in IPCC, 2000a; Houghton, 1997.


Political Climate Change

Full Article (PDF)

by Truman Semans, Director for Markets and Business Strategy at the Pew Center--Appeared in Petroleum Economist, September 2005

Katrina and Global Warming

Back to Main FAQs Page

Was Katrina's Power a Product of Global Warming?

With a unique confluence of geography, expansive lowlands (particularly in the New Orleans area), wetland loss, deforestation, rapid development, large populations of the poor, and a heavy concentration of industry, the Gulf Coast is extremely vulnerable to hurricanes, with or without global warming. Katrina is not the first category 5 hurricane to hit the Gulf Coast (it actually weakened to category 3 shortly before landfall in Louisiana and Mississippi); in fact, of the three previous similar events, two of them occurred in 1935 and 1969, prior to the period of most of the human-induced global warming that has occurred so far. Clearly, then, global warming is not required for an extremely intense hurricane to strike.

But can science tell us whether Katrina's destructiveness was related to global warming? Not directly: science, as a method, is not good at assigning causation for uncontrolled events, and no single weather event can be linked directly to a long-term driver, such as global warming. This inability to draw a definite conclusion, however, in no sense justifies the conclusion that global warming did not influence Katrina.

What science does offer on this question is a general understanding of the physics of tropical storms that can inform reasonable assessment. Because hurricanes draw strength from heat in ocean surface waters, warming the water should generate more powerful hurricanes, on average. Indeed, sea surface temperature records show that the oceans are more than 1 degree F warmer on average today compared to a century ago. On short time scales (days to months), temperatures fluctuate above and below the long-term average, and the water can be warmer or cooler than the average on any given day. But the higher the average, the more likely the water will be warm enough to produce a strong storm on any given day during the hurricane season. Case in point: while Katrina was strengthening from a tropical storm to a category 5 hurricane, as it passed between the Florida Keys and the Gulf Coast, the surface waters in the Gulf of Mexico were unusually warm - about 2 degrees F warmer than normal for this time of year. From this "first-principles" perspective, then, it is no surprise that Katrina became a very powerful storm. While there is no method to determine whether global warming played a role, it is reasonable to say it increased the probability that the Gulf surface water would be unusually warm on any given day, as it was on August 29 when Katrina's intensity peaked.

Beyond inferences from our understanding of storm physics, is there evidence that storms are actually becoming more intense, as we would expect? A study published recently in Nature found that since the early 1950s, the average intensity of tropical storms has increased globally, and this trend correlates very well through time with the increase in average sea surface temperatures in the tropics. These data show a real trend that fits expectations from our basic understanding of climate, and a powerful storm like Katrina makes sense in this context.

So, although we cannot be certain global warming intensified Katrina per se, it clearly has created circumstances under which powerful storms are more likely to occur at this point in history (and in the future) than they were in the past. Moreover, it would be scientifically unsound to conclude that Katrina was not intensified by global warming. A reasonable assessment of the science suggests that we will face similar events again and that powerful storms are likely to happen more often than we have been accustomed to in the past.

Global Warming and Extreme Weather Events

Full Article (PDF)

by Benjamin Preston-- Appeared in Catastrophe Risk Management, Spring 2005

Press Release: New Report Examines Impacts of Storing Carbon

Press Release           
For Immediate Release:  January 19, 2005             

Contact:  Katie Mandes

New report examines the economic and climate impacts of storing carbon in trees

Washington, DC — Cost-effective climate change policies should include storage of carbon dioxide (CO2) in U.S. forests, according to a new report from the Pew Center on Global Climate Change. 

“Climate change is the major global environmental challenge of our time and in order to deal with it in the most cost-effective way, we need to consider the full range of solutions – and that includes carbon storage in forests,” said Eileen Claussen, President of the Pew Center on Global Climate Change.  “If we ignore the potential for forest-based sequestration, any projection of the costs and feasibility of addressing climate change is going to be overly pessimistic and wrong.”

Most analyses of the climate issue have tended to focus on the implications of reducing emissions of carbon dioxide and other greenhouse gases from key industrial and transportation sources. Less attention is paid to the potential for storing (or “sequestering”) carbon in forests and other ecosystems.  Both emissions reduction and carbon sequestration are important strategies for addressing climate change.

The Pew Center report, The Cost of U.S. Forest-based Carbon Sequestration, investigates the potential for incorporating land-use changes into climate policy.  Authored by economists Robert Stavins of Harvard University and Kenneth Richards of Indiana University, the Pew Center report looks at the true “opportunity costs” of using land for sequestration, in contrast with other productive uses. The report also examines the many factors that drive the economics of storing carbon in forests over long periods of time.

Among the authors’ key conclusions: The estimated cost of sequestering up to 500 million tons of carbon per year—an amount that would offset up to one-third of current annual U.S. carbon emissions—ranges from $30 to $90 per ton. On a per-ton basis, this is comparable to the cost estimated for other options for addressing climate change, including fuel switching and energy efficiency.

A sequestration program on the scale envisioned by the authors would involve large expanses of land and significant up-front investment. As a result, implementation would require careful attention to program design and a phased approach over a number of years. Nevertheless, the report offers new evidence that sequestration can and should play an important role in the United States’ response to climate change.

“This report shows that large-scale forest-based sequestration can be a cost-effective tool which should be considered seriously by policymakers,” said the Pew Center's Claussen.

The full text of this and other Pew Center reports is available at


The Pew Center was established in May 1998 by The Pew Charitable Trusts, one of the United States’ largest philanthropies and an influential voice in efforts to improve the quality of the environment. The Pew Center is an independent, nonprofit, and non-partisan organization dedicated to providing credible information, straight answers, and innovative solutions in the effort to address global climate change. The Pew Center is led by Eileen Claussen, the former U.S. Assistant Secretary of State for Oceans and International Environmental and Scientific Affairs.

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