There is growing recognition within the scientific and policy communities that efforts to address climate change should focus not only on substantially reducing carbon dioxide (CO2) emissions, but also on near-term actions to reduce those climate pollutants that remain in the atmosphere for much shorter periods of time. With atmospheric lifetimes on the order of a few days to a few decades, the primary short-lived climate pollutants (SLCPs) are methane, black carbon and certain hydrofluorocarbons. SCLPs are responsible for 30-40 percent of global warming to date. Actions to reduce their emissions could reduce by half the amount of warming that would occur over the next few decades.
In the past few years, considerable attention has shifted to these compounds. New policies (described below) have advanced both within the United States and by the international community aimed at reducing emissions of these pollutants.
Reductions Required in both CO2 and SLCPs
To effectively slow the rate and magnitude of climate change, a strategy that significantly reduces both carbon dioxide and SLCPs is critical:
- Reducing CO2 emissions limits the ultimate amount of warming. Because CO2 represents by far the largest source of climate-warming emissions, and because it stays in the atmosphere for hundreds of years, large reductions in CO2 emissions are required to meet any long-term climate stabilization goal, such as the 2°C goal set by the international community.
- Reducing emissions of short-lived climate pollutants would, on the other hand, effectively slow the near-term rate of climate change. Because SLCPs remain in the atmosphere for a relatively short period of time (compared to CO2) reducing their emissions would result in more immediate benefits. In addition to limiting climate change impacts already underway, including important regional impacts such as glacial melting, SLCP reductions would reduce local air pollution and produce other co-benefits. The U.N. Environment Programme recently estimated that aggressive efforts to reduce SLCPs would avoid 2.4 million premature deaths by 2030 and reduce warming between now and 2040 by a half a degree.
Key Short-Lived Climate Pollutants
Methane has an atmospheric lifetime of about 12 years and a global warming potential of 25 times that of carbon dioxide. It makes up approximately 9 percent of GHG emissions in the United States and roughly 14 percent worldwide. Methane emissions result primarily from oil and gas production and distribution, coal mining, solid waste landfills, cultivation of rice and ruminant livestock, and biomass burning. Reductions in methane emissions also improve local air quality by reducing ground-level ozone, which harms agriculture and human health, and is itself a SLCP.
Black carbon (BC) results from incomplete combustion of biomass and fossil fuels. Its major sources are diesel cars and trucks, cook stoves, forest fires, and agricultural open burning. Black carbon has a short atmospheric lifetime, on the order of a few days to weeks.
Because of a very brief atmospheric lifetime measured in weeks, black carbon's climate effects are strongly regional. BC particles give soot its black color and, like any black surface, strongly absorb sunlight. In snow-covered areas, the deposition of black carbon darkens snow and ice, increasing their absorption of sunlight and making them melt more rapidly. BC may be responsible for a significant fraction of recent warming in the rapidly changing Arctic, contributing to the acceleration of sea ice loss. BC also is contributing to the melting of Himalayan glaciers, a major source of fresh water for millions of people in Asia, and may be driving some of the recent reduction in snowpack in the U.S. Pacific Northwest.
Black carbon's short lifetime also means that its contribution to climate warming would dissipate quickly if emissions were reduced. Additionally, since BC contributes to respiratory and cardiovascular illnesses, reductions in BC emissions would have significant co-benefits for human health, particularly in developing countries.
Hydrofluorocarbons (HFCs) are a family of industrially produced chemicals widely used in refrigeration and air conditioning, foam blowing, and other applications. They were developed to replace ozone-depleting substances (primarily chlorofluorcarbons and hydrochlorofluorocarbons – CFCs and HCFCs) a few decades ago. While HFCs now contribute around 1 percent of total global warming emissions, their use is expected to grow dramatically over time. HFC-134a, the most widely used of these compounds, has an atmospheric lifetime of 13 years and a global warming potential of 1300.
Because ozone-depleting substances (CFCs and HCFCs) are also potent greenhouse gases, their phase-out under the Montreal Protocol has contributed significantly to climate mitigation efforts to date. The treaty's net contribution to climate mitigation (taking into account the growth of HFCs as replacements) is estimated to be five to six times larger than the Kyoto Protocol's first commitment period targets.
Policy Actions in the United States to Limit SLCPs
President Obama included specific actions aimed at reducing emissions of SLCPs in his Climate Action Plan, announced in June 2013. The plan called for the Environmental Protection Agency to use its regulatory authority under the Clean Air Act to limit the use of HFCs where more climate-friendly alternatives are available. In August 2014, under its Significant New Alternatives Policy (SNAP) Program, EPA proposed to limit the use of certain HFCs in mobile air conditioning, specified types of foams and aerosol applications.
In September 2014, the Obama administration announced a series of voluntary commitments from chemical firms, manufacturers and retailers to move rapidly away from HFC-134a and similar compounds and to shift to more environmentally friendly replacements. The announcement also called for the federal government to shift its purchasing to products that use alternatives to HFCs.
The Climate Action Plan also called for additional domestic actions to curb methane emissions, and created an interagency task force to develop a comprehensive strategy for identifying and reducing methane emissions. As a first step in implementing this strategy in April 2014, EPA issued for public comment five white papers on emission sources and reduction technologies for reducing methane in the oil and gas sector. On January 14, 2015, the Administration announced a series of actions aimed at reducing methane emissions in the United States by 40-45 percent from 2012 levels by 2025. The announcement calls for EPA to directly regulate methane emissions from new or modified oil and gas production sources and natural gas processing and transmission sources. It also calls for the agency to issue guidelines for states to reduce VOC emissions from existing oil and gas systems in nonattainment areas and within the Ozone Transport Region. The Bureau of Land Management is to take action to reduce emissions from existing oil and gas wells leased on public lands.
International Initiatives to Limit SLCPs
Climate and Clean Air Coalition: In February 2012, Secretary of State Hillary Clinton announced the creation of the Climate and Clean Air Coalition. Directed specifically at reducing global emissions of SCLPs, this coalition has grown from six governments at the tine of its announcement to 36 state and regional governmental partners, and numerous international and non-governmental organizations. Since its inception, it has developed initiatives across a wide range of sectors including diesel engines, cook stoves, HFCs, oil and gas, and waste.
Montreal Protocol Action on HFCs
A proposal by the United States, Mexico and Canada would require an 85 percent reduction in specified HFCs by 2035 for developed countries, and 2045 for developing countries. While efforts in past years to achieve agreement on this or related proposals have been unsuccessful, the United States and others continue to make the case at annual meetings of the Protocol and in other multilateral and bilateral discussions for using this treaty as a mechanism for achieving worldwide reductions in HFCs. This issue will once again be discussed at the 2015 Meeting of the Parties scheduled for October in Dubai.
High-Level Bilateral and Multilateral Discussions:
President Obama and President Xi of China in a statement issued in June 2013 agreed to work together using the Montreal Protocol to phase-down HFCs.
In St. Petersburg, Russia at the G-20 meeting in September 2013, the member nations included in their final declaration a statement supporting the use of the Montreal Protocol to phasedown HFCs.
In their joint statement on Sept. 30, 2014, President Obama and Prime Minister Modi of India recognized the need to use the institutions and expertise of the Montreal Protocol to reduce emissions of HFCs.
On May 9, 2013, Rep. Scott Peters introduced the Super Pollutant Emissions Reduction Act, which would create a task force aimed at developing strategies and actions to reduce SLCPs.
On September 18, 2014, Senators Christopher Murphy, Susan Collins, and nine others introduced a similar bill, the Super Pollutants Act of 2014.
- Bachmann, John and Seidel, Stephen, Domestic Policies to Reduce the Near-Term Risk of Climate Change. Center for Climate and Energy Solutions, 2013.
This paper sets out a series of cost-effective steps that the Obama Administration can implement under existing authorities that would deliver substantial near-term reductions in the rate of climate change.
- Fast Action to Reduce the Risks of Climate Change: U.S. Options to Limit Short-Lived Climate Pollutants, Feb. 2012
- Bodansky, Daniel, Multilateral Climate Efforts Beyond the UNFCCC, Center for Climate and Energy Solutions, Nov. 2011.
This report looks at a number of multilateral entities that could play a role in addressing certain of the SLCFs including: the Montreal Protocol as a possible venue for HFCs and the Convention on Long-Range Transboundary Air Pollution as a possible venue for BC, methane and other ozone-precursors.
- Bachmann, John, Black Carbon: A Science/Policy Primer, Center for Climate and Energy Solutions (formerly the Pew Center on Global Climate Change), 2009.
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.
- What is Black Carbon?, Center for Climate and Energy Solutions (formerly the Pew Center on Global Climate Change), April 2010.
This factsheet provides an overview of black carbon as a major contributor to global climate change. It describes why reducing black carbon is a win-win scenario for both climate and health reasons.
- Read Eileen Claussen's statement on the Climate and Clean Energy Coalition to Reduce Short-Lived Climate Pollution
- UNEP and WMO, Integrated Assessment of Black Carbon and Tropospheric Ozone: Summary for Decision Makers, 2011
- UNEP, Near-term Climate Protection and Clean Air Benefits: Actions for Controlling Short-Lived Climate Forcers, 2011.
- Montzka, S.A., Dlugokency,E.J., Butler, J.H., Non-CO2 Greenhouse Gases and Climate Change. Nature, 476, 43-50. August 2011.
- Shindell, D. et. al., Simultaneously Mitigating Near-Term Climate Change and Improving Human Health and Food Security, Science, 335, 183-188 Jan 13, 2012.
- UNEP, HFCs: A Critical Link in Protecting Climate and the Ozone Layer, Nov. 2011.
- Velders, G.J.M., Fahey, D.W., Daniel, J.S., McFarland, M, Andersen, S.O., The Large Contribution of Projected HFC Emissions to Future Climate Forcing. Proc. Nat. Acad. Sci. 106, 10949-10954. 2009
- US EPA, Report to Congress on Black Carbon: March 2012.
International Forums Focused on SLCPs:
- Climate and Clean Energy Coalition to Reduce Short-Lived Climate Pollution
- Secretary of State Hillary Rodham Clinton's Remarks at the Climate and Clean Air Coalition To Reduce Short-Lived Climate Pollutants Initiative
- Briefing on Global Climate Change and Clean Air Initiative
- Arctic Council
Arctic Council, Progress Report and Recommendation for Ministers, Arctic Council Task Force on Short-lived Climate Forcers, 2011
- Montreal Protocol
- EPA, North American Amendment Proposal to Phase-Down HFCs under the Montreal Protocol
- UNEP, Federated States of Micronesia Proposed Amendment to control HFCs under the Montreal Protocol, May 2011
- Ministerial Meeting
Co-Chairs Summary, Ministerial Meeting on Short-lived Climate Forcers, Mexico City, 2011
A common analogy to explain the link between climate change and extreme weather is gambling with “loaded dice.” For people who aren’t the gambling type but love America’s pastime, perhaps Barry Bonds’ homerun statistics would be more enlightening, or at least more entertaining. A new video from the National Center for Atmospheric Research draws an analogy between a batter on steroids and the “doping” of the atmosphere with manmade CO2.
Learn about the Climate Leadership Conference, Australia's new carbon pricing mechanism, the Make an Impact energy conservation challenge, and more in C2ES's January 2012 newsletter.
The Center for Climate and Energy Solutions (C2ES) was named the world’s top environmental think tank in a global survey of top public policy research institutes.
The University of Pennsylvania’s 2011 Global Go-To Think Tank Rankings are based on a survey of more than 1,500 policymakers, scholars, journalists, think-tank executives and others worldwide. The survey assessed more than 5,300 organizations nominated in 30 categories to create a global list of top think tanks by region and policy area.
C2ES’s predecessor organization, the Pew Center on Global Climate Change, was named the world’s top environmental think tank in the same survey in 2009. The center began operating as C2ES in November 2011, and is listed in the new survey under its former name.
“While our name has changed, we remain as committed as ever to fact-based analysis and common-sense solutions to our climate and energy challenges,” said C2ES President Eileen Claussen. “We are thrilled to again be recognized as the world’s top environmental think tank. I’d like to commend the C2ES staff and thank all of our partners and supporters in the United States and abroad for helping to make this possible.”
The independent, nonpartisan center provides impartial information and analysis on energy and climate challenges; convenes policymakers and stakeholders to work toward consensus solutions; works with members of its Business Environmental Leadership Council and others to promote on-the-ground action; and promotes pragmatic, effective climate and energy policies at the state, national and international levels.
The annual survey, first published in 2007, is directed by James G. McGann, assistant director of the University of Pennsylvania’s International Relations Program and director of the Think Tanks and Civil Society Program.
The World Resources Institute and Chatham House ranked second and third, respectively, among the study’s top 30 environmental groups. Brookings Institution was named the top overall think tank. Additional categories in which the report ranks organizations include health policy, international development, and security and international affairs, among others.
The complete study, released in January 2012, is available online here.
More about C2ES's work to advance climate and energy solutions can be found here.
Extreme Weather and Climate Change
Understanding the Link, Managing the Risk
Updated December 2011
Thousands of record-breaking weather events worldwide bolster long-term trends of increasing heat waves, heavy precipitation, droughts and wildfires. A combination of observed trends, theoretical understanding of the climate system, and numerical modeling demonstrates that global warming is increasing the risk of these types of events today. Debates about whether single events are “caused” by climate change are illogical, but individual events offer important lessons about society’s vulnerabilities to climate change. Reducing the future risk of extreme weather requires reducing greenhouse gas emissions and adapting to changes that are already unavoidable.
Typically, climate change is described in terms of average changes in temperature or precipitation, but most of the social and economic costs associated with climate change will result from shifts in the frequency and severity of extreme events. This fact is illustrated by a large number of costly weather disasters in 2010, which tied 2005 as the warmest year globally since 1880. Incidentally, both years were noted for exceptionally damaging weather events, such as Hurricane Katrina in 2005 and the deadly Russian heat wave in 2010. Other remarkable events of 2010 include Pakistan’s biggest flood, Canada’s warmest year, and Southwest Australia’s driest year. 2011 continued in similar form, with “biblical” flooding in Australia, the second hottest summer in U.S. history, devastating drought and wildfires in Texas, New Mexico and Arizona as well as historic flooding in North Dakota, the Lower Mississippi and in the Northeast.
Munich Re, the world’s largest reinsurance company, has compiled global disaster for 1980-2010. In its analysis, 2010 had the second-largest (after 2007) number of recorded natural disasters and the fifth-greatest economic losses. Although there were far more deaths from geological disasters—almost entirely from the Haiti earthquake—more than 90 percent of all disasters and 65 percent of associated economic damages were weather and climate related (i.e. high winds, flooding, heavy snowfall, heat waves, droughts, wildfires). In all, 874 weather and climate-related disasters resulted in 68,000 deaths and $99 billion in damages worldwide in 2010.
The fact that 2010 was one of the warmest years on record as well as one of the most disastrous, begs the question: Is global warming causing more extreme weather? The short and simple answer is yes, at least for heat waves and heavy precipitation. But much of the public discussion of this relationship obscures the link behind a misplaced focus on causation of individual weather events. The questions we ask of science are critical: When we ask whether climate change “caused” a particular event, we pose a fundamentally unanswerable question (see Box 1). This fallacy assures that we will often fail to draw connections between individual weather events and climate change, leading us to disregard the real risks of more extreme weather due to global warming.
Climate change is defined by changes in mean climate conditions—that is, the average of hundreds or thousands events over the span of decades. Over the past 30 years, for example, any single weather event could be omitted or added to the record without altering the long-term trend in weather extremes and the statistical relationship between that trend and the rise in global temperatures. Hence, it is illogical to debate the direct climatological link between a single event and the long-term rise in the global average surface temperature.
Nonetheless, individual weather events offer important lessons about social and economic vulnerabilities to climate change. Dismissing an individual event as happenstance because scientists did not link it individually to climate change fosters a dangerously passive attitude toward rising climate risk. The uncertainty about future weather conditions and the illogic of attributing single events to global warming need not stand in the way of action to manage the rising risks associated with extreme weather. Indeed, such uncertainty is why risk managers exist – insurance companies, for example – and risk management is the correct framework for examining the link between global climate change and extreme weather.
An effective risk management framework accommodates uncertainty, takes advantage of learning opportunities to update understanding of risk, and probes today’s rare extreme events for useful information about how we should respond to rising risk. Risk management eschews futile attempts to forecast individual chaotic events and focuses on establishing long-term risk certainty; that is, an understanding of what types of risks are increasing and what can be done to minimize future damages. An understanding of the meaning of risk and how it relates to changes in the climate system is crucial to assessing vulnerability and planning for a future characterized by rising risk.
For more on the relationship between extreme weather and climate change, visit our Extreme Weather web page, where you'll find our extreme weather events map, along with other reports and C2ES resources.
 Karl, T. R., Meehl, G. A., Miller, C. D., Hassol, S. J., Waple, A. M., & Murray, W. L. (2008). Weather and Cliamte Extremes in a Changing Climate; Regions of Focus: North America, Hawaii, Caribbean, and U.S. Pacific Islands. A Report by the U.S. Climate Change Science Program and the Subcommittee on Global Change Research. Washington, D.C., USA: Department of Commerce, NOAA's National Climatic Data Center.
 BBC News. (2011, January 1). Australia's Queensland faces 'biblical' flood. Retrieved May 19, 2011, from http://bbc.in/fNzGgK; Associated Press. (2011, May 1). Federal fire crews bring expertist to huge TX fire. Retrieved May 19, 2011, from http://bit.ly/iz6JRs; Associated Press. (2011, June 16). Concern over human-caused blazes grows as wind-driven wildfires promp more evacuations. Retrieved June 22, 2011, from Washington Post: http://wapo.st/iWxirz; Sulzberger, A.G. (2011, June 26). In Minot, N.D., Flood Waters Stop Rising. Retrieved November 22, 2011, from New York Times: http://nyti.ms/ufT9jY; Doyle, R. (2011, September 8) U.S. sweltered through hottest summer in 75 years. Retrieved November 22, 2011, from USA Today: http://usat.ly/o73h4o; Robertson, C. (2011, May 15). Record Water for a Mississippi River City. Retrieved November 22, 2011, from New York Times: http://nyti.ms/lp0cTA; Freedman, A. (2011, September 12). Historic Flooding Recedes in Pennsylvania, New York; at least 15 dead. Retrieved November 22, 2011, From Washington Post: http://wapo.st/qvywOo
 Karl et al., Weather and Cliamte Extremes in a Changing Climate, Op. cit.
For the second year in a row, unprecedented numbers of extreme weather events have occurred across the globe. However, more of 2011’s impacts occurred in the United States. From the drought in Texas to the floods in the Midwest and Northeast, this past year underscored the huge economic costs associated with extreme weather. While specific weather events are not solely caused by climate change, the risks of droughts, floods, extreme precipitation events, and heat waves are already climbing as a result of climate change. This year reminded us of our vulnerability to those events.
C2ES's December 2011 features updates from the 17th annual Conference of the Parties (COP17) in Durban, South Africa, policy options for a clean energy standard, a blog post on the landmark new fuel economy standards, and more.
Friday, December 2, 2011
12:30 -2:00 pm
B-339 Rayburn House Office Building
2011 has been a record year for weather disasters. From historic drought in Texas to record-breaking flooding in North Dakota, to an unprecedented number (> 5600) of record high temperatures across the United States, much of the country has seen severe damage from extreme weather. The year is not yet over, and economic losses already exceed $45 billion.
This lunch briefing with leading experts examines extreme weather hazards, with a case study on the Texas drought, their relationship to changes in our climate, and how the country can better prepare for such events. Speakers at this lunch briefing include:
- Michael Oppenheimer, Albert G. Milbank Professor of Geosciences and International Affairs, Princeton University; Coordinating Lead Author, IPCC Report on Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation
- John Nielsen-Gammon, Texas State Climatologist and Regents Professor of Atmospheric Sciences, Texas A&M University
- Frank Nutter, president of the Reinsurance Association of America
Moderated by Jay Gulledge, Senior Scientist and Director for Science and Impacts, Center for Climate and Energy Solutions
Sponsored by the American Association for the Advancement of Science (AAAS), the American Geophysical Union (AGU), and Center for Climate and Energy Solutions (C2ES).
The Intergovernmental Panel on Climate Change (IPCC) released a “special report” (that’s what they call topical reports they publish in between their better known comprehensive assessments) today that is worth a close look for anyone who wants to start getting ready for a future with weirder and often harsher weather.
About a year ago I published an opinion editorial taking the Intergovernmental Panel on Climate Change (IPCC) to task for neglecting risk-based information to help decision makers cope with inevitable uncertainties about the future impacts of climate change:
Since uncertainty is endemic to the future, when the second IPCC assessment concluded in 1995 that ‘The balance of evidence suggests a discernable human influence on the global climate’, the IPCC should have reconvened around the risk implications of this probable human influence. Instead, it redoubled its effort to reduce physical science uncertainties [which will not be resolved before action is required].
For those of you who came to our website today expecting to find information and resources from the Pew Center on Global Climate Change, please don’t click away. Today we announced an exciting transition. We are now C2ES — the Center for Climate and Energy Solutions. In addition to changing our name, we’ve refreshed our mission and strategic approach, updated our website, and made other changes to ensure that we can continue to craft real solutions to the energy and climate challenges we face today.
Yes, a great deal has changed in the last 24 hours. But what hasn’t changed is the need for straight talk, common sense and common ground. Today’s climate and energy issues present us with real challenges — and real opportunities as well. This is about protecting the environment, our communities and our economy. And it is about building the foundation for a prosperous and sustainable future.