The cold weather continues across much of the Unites States, Europe, and central Asia as the Arctic Oscillation remains in a strong “negative” state, forcing cold Arctic air down to the mid-latitudes. A couple of weeks ago I explained why more frequent heavy snowfall events could be a consequence of global warming for mid-latitude areas near large bodies of water, like Washington, D.C., and Syracuse, New York (see figure).
|The average amount of annual snowfall has been increasing in Syracuse, New York, for most of the past century. (SOURCE: Increasing Great Lake–Effect Snowfall during the Twentieth Century: A Regional Response to Global Warming? Journal of Climate vol. 16, pp. 3535-3342, Figure 1)|
On January 31, I noticed a forecast for lake-effect snowfall around the Great Lakes on Weather.com: “Lake-effect snows are also possible near the central and western Great Lakes today and tonight.”
On December 19, Washington, D.C. was buried by two feet of snow, setting a new record for snowfall during the entire month of December and paralyzing the city for three days. As my neighbor and I shoveled out from the storm, he stopped for a moment, grinned, and asked, “So what happened to global warming?” Boy was he surprised when I said, “Glad you asked,” and launched into a 15-minute oratory on why global warming might mean more, not less, extreme snowfall for some parts of the world.
Before continuing, I need to reiterate that no single weather event can be attributed to global warming. So the question here is not, “What caused the heavy snowfall on December 19?” The question is, “Is heavy snowfall or unusually cold weather inconsistent with global warming?”
You need two things to create heavy snowfall: moist air and cold air. The two generally don’t occur in the same air mass because cold air can’t hold much moisture. So you need two air masses, one that is warm and moist and one that is cold and dry, to collide with each other. That is exactly what happened over the Mid-Atlantic region on December 19.
This condition is not only consistent with global warming, but it can be expected to occur more frequently in certain places as a direct result of global warming. It takes warmth to generate moist air. First, you need warmth to evaporate enough water from lakes or oceans to generate a massive snowstorm. Second, you need warm air to keep the water vapor aloft so that it doesn’t rain out before it finds a cold air mass to collide with. When I asked weatherman Joe Witte where the moisture that ended up in my snow shovel came from, he said, “Some of the moisture came out of the Gulf of Mexico AND some from the warm Atlantic ocean with the VERY warm (70s!) Gulf Stream along the East coast acting as a hot plate for evaporation of moisture into the cold dry air.”
|(SOURCE: NOAA polar-orbiting satellite data compiled by Rutgers University Coastal Ocean Observation Lab)|
Although the past few weeks have been very cold in the eastern United States, Joe pointed me to NOAA satellite measurements that found sea surface temperatures in the Gulf of Mexico and the Atlantic Ocean to be 1 to 3 °F warmer than normal during the week before the big snowstorm hit (see figures above). There is strong scientific evidence showing that, on average, the oceans are warmer today than they were a century ago because of human-induced global warming. So the warm ocean temperatures that fed the heavy snowfall are consistent with global warming. In fact, because of global warming, we should expect such conditions to be more common today than in the past and even more common in the future as warming continues.
So where did the cold, dry air come from? Global warming is about changes in long-term averages and not about single events; it does not mean an end to cold weather. Instead, it means that cold weather will become less frequent and hot weather more frequent when averaged over decades. In fact, both of these trends have been observed over the past 50 years in the United States and globally. So, even with global warming we will have cold winters, just fewer of them. It is also important to remember that a cold winter here doesn’t mean a cold winter everywhere. In fact, many parts of the world, including the Arctic and the tropics, are having an unusually warm winter. The current cold snap is concentrated in the mid-latitudes of the northern hemisphere, and there will always be the potential for cold Arctic air masses to visit the mid-latitudes from time to time.
The current cold snap is related to a known weather pattern called the Arctic Oscillation. When the Arctic Oscillation switches between “positive” and “negative” states, it simply shifts heat between the Arctic and the mid-latitudes. Scientists call this kind of pattern “internal variability,” and it does not change the total amount of heat in the climate system. Internal variability can create strong differences in the weather from year to year and place to place, but these shifts average out to zero net climate change over decades. Only a net change in the total amount of heat in the climate system can change the long-term average climate, and that is the nature of global warming.
When the mid-latitudes get periodic blasts of cold Arctic air, global warming makes it more likely that the cold air from up north will collide with moist, warm air from down south, creating more heavy snowfall events in mid-latitude areas near large bodies of water. A similar phenomenon is affecting the Great Lakes region. Syracuse, New York is one of the snowiest places in the country, but it and other areas around the Great Lakes are getting even snowier! Because the Great Lakes are getting warmer, they are icing over later and melting earlier than they used to. Without the ice, water can evaporate and enter the atmosphere over the lakes later in the fall and earlier in the spring. When winds blow this moist air over the land where temperatures are lower, we get the famous “lake effect” snow. With more open water during the winter, more lake effect snow is falling.
These are the cold facts of global warming.
Jay Gulledge is Senior Scientist and Program Manager for Science & Impacts
Domestically and internationally, climate action in 2009 laid critical groundwork for potential breakthroughs in Congress and global negotiations in 2010. Yet with an issue as complex and political as climate change, turning groundwork into policy is a challenge. 2010 will undoubtedly be a pivotal year for climate change – but first it is instructive to take a look back at what happened in 2009 and how that shaped where we are today.
We captured these highlights in our annual Year-in-Review Newsletter – a useful compilation of 2009’s big climate change stories and related insights. The year’s major domestic action included passage of the landmark House climate and clean energy bill along with numerous Obama administration efforts to improve our climate and economy. These accomplishments included the stimulus bill’s $80 billion in clean energy-related funding and EPA actions, including the endangerment finding, the greenhouse gas reporting rule, and stricter auto-efficiency standards.
Copenhagen consumed international climate attention in 2009, culminating in the pre-dawn hours of December 19 when final touches were put on an accord directly brokered by President Obama and a handful of key developing country leaders. While many questions remain after Copenhagen, our summary of the conference provides a sound starting point for grasping what transpired at the year’s largest climate event.
The lead-up to 2009’s main events required a great deal of work, and some of the year’s highlights include the detailed Blueprint for Climate Action released one year ago this month by the influential business-NGO coalition U.S. Climate Action Partnership (USCAP). More industry leaders also showed support for mandatory climate action by joining our Business Environmental Leadership Council (BELC). And efforts to reach business communities, employees, and families expanded through the Make An Impact program. In partnerships with aluminum manufacturer Alcoa and utility Entergy, we continue to provide individuals with strategies to save energy and money while protecting the environment.
We continued to educate policy makers and opinion leaders, producing reports, analyses, and fact sheets on topics ranging from clean-energy technologies, climate science, competitiveness, and adaptation. Featuring expert insights and thoughtful opinions, we informed broad audiences about the immediate need for climate action. And our timely, relevant work moves forward in 2010 as we seek progress in addressing the most important global issue of our time.
Tom Steinfeldt is Communications Manager
Climate Change Impacts and Adaptation
January 8, 2010
The American Association for the Advancement of Science (AAAS), The American Geophysical Union (AGU), The American Meteorological Society (AMS), The Ecological Society of America (ESA), and the Pew Center on Global Climate Change held a briefing on climate change impacts and adaptation.
Click here for a video of the event.
Human-caused climate change is well underway and almost certain to continue in the decades ahead. Comprehensive risk management strategies will include efforts both to reduce greenhouse gas emissions (mitigation) and to enhance society’s ability to cope with climate impacts (adaptation). Mitigation and adaptation often get mistaken for competing, mutually exclusive alternatives when they are really complimentary approaches with differing strengths and limitations. This briefing will examine the nature of climate impacts occurring within the United States, and explore options for dealing with those impacts.
- Thomas R. Karl, Director, NOAA’s National Climatic Data Center; Lead, NOAA Climate Services; and President, American Meteorological Society
- Kristie L. Ebi, Executive Director, Intergovernmental Panel on Climate Change (IPCC) Working Group 2 Technical Support Unit - Impacts, Adaptation, and Vulnerability
- Katharine L. Jacobs, Executive Director, Arizona Water Institute; and Professor, University of Arizona Soil, Water and Environmental Science Department
- Susanne Moser, Director and Principal Researcher of Susanne Moser Research & Consulting; and Research Associate at the University of California-Santa Cruz Institute for Marine Sciences
Moderator: Paul Higgins, Senior Policy Fellow, American Meteorological Society
Click here for a summary of speaker remarks and biographies.
Calculating the Benefits of Climate Policy: Examining the Assumptions of Integrated Assessment Models
Prepared for the Pew Center on Global Climate Change
by Michael D. Mastrandrea
Woods Institute for the Environment, Stanford University
Download full paper (pdf)
Policy-relevant results of Integrated Assessment Models (IAMs) are sensitive to a number of uncertain assumptions that govern model simulation of the climate, society, and the policy response to climate change. Uncertainties remain in understanding of the rate and magnitude of climate change, the nature and severity of climate impacts, and the ability to cope with those impacts. Methods for quantifying and comparing climate damages across different regions and different time periods are fiercely debated. This paper examines assumptions that are central to model estimates of the benefits of climate policy in three well-known IAMs, and discusses their consistency with current natural and social scientific research. Different IAMs take different approaches to dealing with these uncertainties, and understanding their assumptions is critical to interpreting their results, since those results can change dramatically when assumptions are varied.
December 22, 2009
Contact: Tom Steinfeldt, (703) 516-4146
AVIATION AND MARINE TRANSPORTATION OFFER BIG POTENTIAL EMISSIONS REDUCTIONS
Report Finds Extensive Options Currently Available
WASHINGTON, D.C. – The potential for reducing greenhouse gas (GHG) emissions from global aviation and marine transportation is considerable — reductions of more than 50 percent below business-as-usual (BAU) levels by 2050 are possible, according to a new report from the Pew Center on Global Climate Change.
The report, Aviation and Marine Transportation: GHG Mitigation Potential and Challenges, examines growth projections for emissions from both aviation and marine transportation and options to reduce those emissions. Aviation and marine transportation combined are responsible for approximately 5 percent of total GHG emissions in the United States and 3 percent globally and are among the fastest growing modes in the transportation sector. Under business-as-usual forecasts, CO2 emissions from global aviation are estimated to grow 3.1 percent per year over the next 40 years, resulting in a 300 percent increase in emissions by 2050.International marine transportation emissions are estimated to grow by 1 to 2 percent per year, increasing by at least 50 percent over 2007 levels by 2050. Controlling the growth in aviation and marine transportation GHG emissions will be an important part of reducing emissions from the transportation sector.
A range of near-, medium- and long-term mitigation options are available to slow the growth of energy consumption and GHG emissions from aviation and marine shipping. These options include improvements in operational efficiency, improvements in the energy efficiency of engines and the design of air and marine vessels, and transitioning to less carbon-intensive fuels and transportation modes. Implementation of these options could result in reductions of more than 50 percent below BAU levels by 2050 from global aviation and more than 60 percent for global marine shipping. For these reductions to be realized, however, international and domestic policy intervention is required. Developing an effective path forward that facilitates the adoption of meaningful policies remains both a challenge and an opportunity.
“Aviation and marine shipping are two of the fastest growing modes of transportation,” said Eileen Claussen, President of the Pew Center on Global Climate Change. “Their greenhouse gas emissions are growing rapidly as well. To protect the climate, we need to reduce emissions across the entire economy. Aviation and marine shipping are part of the climate problem, and this report shows that they can be part of the solution.”
Aviation and Marine Transportation: GHG Mitigation Potential and Challenges also examines policy options for achieving reductions in GHG emissions from these transportation modes. The paper, authored by David McCollum and Gregory Gould of the University of California at Davis and David Greene from Oak Ridge National Laboratory, explains the challenges, examines policy efforts to date, and explores both domestic and international policy options for addressing emissions from aviation and marine transportation.
Key sections of the paper include:
- An introduction to aviation and marine transportation and a discussion of the determinants of their GHG emissions;
- An overview of current emissions trends and growth projections;
- An explanation of the technological mitigation options and potential GHG emission reductions; and
- Policy options at both the domestic and international level to achieve deep and durable reductions in emissions.
For more information about global climate change and the activities of the Pew Center, visit www.c2es.org.
The Pew Center was established in May 1998 as 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. The Pew Center is led by Eileen Claussen, the former U.S. Assistant Secretary of State for Oceans and International Environmental and Scientific Affairs.
Today, the Obama Administration has formally recognized the importance of black carbon as a component of broader policies to address climate change. At the UN Climate Change Conference in Copenhagen, Nancy Sutley, the Chair of the Council on Environmental Quality, announced an initiative aimed at reducing emissions of black carbon. The United States is committing $5 million towards international cooperation to reduce black carbon emissions in and around the Arctic. According to Chair Sutley, the new initiative will include investments to study the effects of black carbon, demonstrate options for reducing emissions, and begin to quantify both the climate and public health benefits of reducing emissions. The initiative will focus on diesel engines (both on-road and non-road, including those used for port operations), older district heating and industrial facilities, and agricultural and forest fires.
We just released a new white paper highlighting the climate impacts of black carbon (Black Carbon: A Science/Policy Primer). Over the last decade, a growing body of evidence indicates that soot and smoke are major contributors to climate change. Black carbon, a component of soot, warms the air by absorbing sunlight in the atmosphere, changes rainfall patterns and, when deposited on snow and ice, accelerates melting. Black carbon is produced by both natural processes and human activity from the incomplete combustion of fossil fuels, biofuels, and biomass. Primary sources include diesel engines, small industrial sources, residential coal and solid biofuels for cooking and heating, and agricultural and forest fires.
The new paper summarizes current knowledge on the climate effects of soot components (black carbon and organic particles) and identifies emission sources and technologies to mitigate their impacts. It also presents perspectives on the potential role of soot mitigation approaches in developing more comprehensive climate strategies.
Black carbon remains in the atmosphere for only days to weeks, meaning it has strong regional climate effects. Recent studies suggest that black carbon may be responsible for 30-50 percent of recent warming in the Arctic, contributing to the acceleration of Arctic sea ice melting. Loss of Arctic sea ice is one potential “tipping point” that could lead to rapid warming and irreversible climate change. Black carbon is also driving increased melting of the glaciers in the Himalayan Plateau, upon which some 40 percent of the world’s population depends for fresh water. Reductions in black carbon would help address these issues and also would have many co-benefits, particularly in public health and especially in the developing world.
Controlling emissions of CO2 and long-lived greenhouse gases must remain the centerpiece of policies to address climate change, since they ultimately drive the Earth’s temperature in the long term. However, reducing black carbon emissions represents a win-win scenario: it would have an immediate cooling effect on the Earth’s climate, potentially delaying temperature increases in the short run and helping reduce the risk of irreversible tipping points in the climate system, and it would reduce air pollution, significantly improving public health.
Jeremy Richardson is Senior Fellow for Science Policy
Prepared for the Pew Center on Global Climate Change
by John Bachmann, Vision Air Consulting, LLC
Over the last decade, a growing body of evidence indicates that soot and smoke from incomplete combustion are major contributors to climate change. Black carbon, a soot component, is a potent climate driver that absorbs sunlight in the atmosphere, changes rainfall patterns, and when deposited on snow and ice, accelerates melting. In addition, soot can cause direct effects on health and agriculture. Climate and other effects of soot are magnified in broad regions where the strongest source emissions occur, but transported soot is also a major concern in the Arctic. The short atmospheric lifetime of soot particles also means that emissions reductions produce nearly immediate results, in contrast to most greenhouse gases (GHGs).
The principal source categories include diesel engines, small industrial sources, residential coal and solid biofuels for heating and cooking, and open biomass burning for agriculture and forestry. Control and mitigation approaches exist, but the small size and wide dispersion of these sources present significant challenges. The available evidence suggests that appropriately targeted soot controls have the potential to accelerate and enhance climate and air quality related public health benefits when used as a complement to overall climate strategies centered on greenhouse gases. Consideration of such controls is, however, subject to a number of scientific and technical uncertainties and complexities regarding emissions, controls, and the net effect of addressing some soot sources on both global and regional scales. This paper summarizes current knowledge on the effects of soot components—black carbon and organic particles—on climate, and identifies sources and technologies to mitigate their impacts. It also presents perspectives on the potential role of soot mitigation approaches in developing more comprehensive climate strategies.
This Thanksgiving, I’m thankful we base policy decisions on peer-reviewed science instead of emails!
The kerfuffle over email correspondence hacked from a server at the University of East Anglia’s Climatic Research Unit is making climate change deniers giddy. But just like all the other non-smoking guns they’ve waived around over the years, this “mushroom cloud” will soon blow away. Nothing has come to light that undermines scientific assessments of the climate system, which are firmly anchored in peer-reviewed scientific publications, not emails.
Some of the past “smoking guns” that were supposed to put the theory of human-induced climate change in an early grave are among the hot topics flying around in the hacked emails. One was a paper by Soon and Baliunas published in a peer-reviewed journal called Climate Research in 2003. That paper was supposed to put to rest the conclusion of the 2001 IPCC report that the late 20th century was warmer than any previous period in the past millennium, but it was quickly and thoroughly refuted in the peer-reviewed literature (not in emails). Another was a 2005 paper by McIntyre and McKitrick in an often-not-peer-reviewed journal called Energy & Environment. This paper had the same goal as the first one, but it too was rebutted in the peer-reviewed literature and in a report by the National Academy of Sciences (not in emails). In the emails, climate scientists complained about these papers and expressed frustration that they were published in spite of serious flaws. However, policymakers did not use these emails to help them determine America’s policy actions on climate change.
Much of the bickering in the emails boils down to scientists’ irritation over serious breaches of the normal peer review system to get denialist papers published (see here, here and here). The publisher of Climate Research (CR) admitted that the major conclusions of the paper by Soon and Baliunas “cannot be concluded convincingly from the evidence provided in the paper. CR should have requested appropriate revisions of the manuscript prior to publication.” The paper was so bad that three editors resigned in protest over its publication. The paper by McIntyre and McKitrick (2005) wasn’t peer reviewed at all and the editor of Energy & Environment openly stated, “I'm following my political agenda – a bit, anyway. But isn't that the right of the editor?” Scientists value the peer review process and they find it unfair and objectionable when they subject their own work to potential rejection while others circumvent this critical step in the scientific process to force low-quality research into the debate.
Luckily, none of this matters since the scientific assessments produced to inform policymakers about the science of climate change are based on peer-reviewed science publications, not on the opinions of individuals expressed in email correspondence. As happens in the normal scientific process, when the occasional bad paper slips through the peer review cracks it gets refuted through subsequent scrutiny in the peer-review literature. In the end, what may be said in emails doesn’t matter; the scientific peer-review process will prevail.
Jay Gulledge is Senior Scientist and Program Manager for Science & Impacts
This morning, the House Select Committee on Energy Independence and Global Warming held a hearing titled “Building US Resilience to Global Warming Impacts.” The hearing took place just as the Government Accountability Office released a new report finding that US reaction to climate change is happening on an ad hoc basis and is not coordinated among Federal, state, and local agencies.
Given the absence of a coordinated Federal adaptation strategy, we’ve been looking at what the options might be to fill that void. As the Pew Center’s Steve Seidel stated in his testimony to the Committee, an improved Federal mechanism would begin with each agency developing an adaptation strategic plan to build greater resilience to climate change into its programs and mission. He pointed to a recent announcement by the Dept. of Interior as an example. A National Climate Service that can develop and communicate credible and actionable climate scenarios and projections for use in adaptation planning by Federal, state and local governments and the private sector is also needed.
Executive office leadership is critical. After reviewing other climate-related interagency programs in existence, it’s clear that a national adaptation program needs to be established and chaired or co-chaired by CEQ or the Office of Science and Technology Policy. To ensure that adaptation is truly “mainstreamed” by the federal government, CEQ should also update NEPA regulations to require the consideration of adaption needs in all major federal actions.
Michael Tubman is a Congressional Affairs Fellow