Climate Change 101 series

To inform the climate change dialogue, the Center for Climate and Energy Solutions has produced a series of brief reports entitled Climate Change 101: Understanding and Responding to Global Climate Change, Updated January 2011.

These reports provide a reliable and understandable introduction to climate change. They cover climate science and impacts, climate adaptation, technological solutions, business solutions, international action, federal action, recent action in the U.S. states, and action taken by local governments. The overview serves as a summary and introduction to the series.

Read the entire series or jump to a single report:
OverviewScience and ImpactsAdaptationTechnologyBusiness International FederalStateLocal • Cap and Trade

For more information, be sure to listen to our Climate Change 101 podcast series


Complete101Climate Change 101: Understanding and Responding to Global Climate Change

The complete set of six reports plus the overview in one volume.




OverviewClimate Change 101: Overview

This overview summarizes the key points from each of the Climate Change 101 reports.




Climate Change 101 The Science and ImpactsClimate Change 101: Science and Impacts

This report provides an overview of the most up-to-date scientific evidence and also explains the causes and projected impacts of climate change.




Adaptation 101 Climate Change 101: Adaptation

This report details how adaptation planning at the local, state and national levels can limit the damage caused by climate change.




TechnologyClimate Change 101: Technological Solutions

This piece discusses the technological solutions both for mitigating its effects and reducing greenhouse gas emissions now and into the future.




Business SolutionsClimate Change 101: Business Solutions

This report discusses how corporate leaders are helping to shape solutions.




InternationalClimate Change 101: International Action

This report discusses what will be needed for an effective global effort, one calling for commitments from all the world's major economies.




Federal ActionClimate Change 101: Federal Action

This report discusses federal policy options that can put the country on the path toward a lower-carbon future.




State ActionClimate Change 101: State Action

This report highlights states' efforts as they respond to the challenges of implementing solutions to climate change.



Local Action Climate Change 101: Local Action

This report describes the actions taken by cities and towns.




Cap and trade 101Climate Change 101: Cap and Trade

This report explains the details of cap and trade.



The Earth’s climate is rapidly changing. In the United States and other nations, people are seeing how the impacts of rising global temperatures affect their communities, their livelihoods, and the natural environment. Substantially reducing greenhouse gas emissions is essential to avoiding the worst impacts of climate change. But mitigation alone is not enough. Even with emission reductions, some warming will still occur. Adaptation planning at the local, state, and national levels can limit the damage caused by climate change, as well as the long-term costs of responding to climate-related impacts that are expected to grow in number and intensity in the decades to come.

To learn more about adaptation, read Climate Change 101: Adaptation and check out the additional resources below. 

U.S. Federal Adaptation Resources:

U.S. States & Regions Adaptation Resources:

Markets & Business Adaptation Resources:

International Adaptation Resources:

Climate Change Risks in the Context of Scientific Uncertainty

Full Article available for download (PDF)

by Jay Gulledge, Senior Scientist and Program Manager for Science and Impacts— Appeared in The Global Politics of Energy, a book published by The Aspen Institute, May 2008

Nelson Institute Earth Day Conference 2008

Promoted in Energy Efficiency section: 

Scientific Uncertainty and Climate Change Risks
Keynote Address by Pew Center Senior Scientist Dr. Jay Gulledge
2nd Annual Nelson Institute Earth Day Conference
April 16, 2008 - Madison, Wisconsin
Click here to view the presentation.

Pew Center Senior Scientist Dr. Jay Gulledge discusses environmental risks of climate change in his keynote address to the 2nd Annual Nelson Institute Earth Day Conference. In his remarks, Dr. Gulledge explains that despite uncertainty, scientists can be highly confident in their findings about global warming. For example, data show the rise in global surface temperature and atmospheric concentrations of greenhouse gases in the past 50 years. It is the confident conclusion of the scientific community at large that the greenhouse gases generated by human activity are driving this warming trend.

The conference, entitled Sustaining Wisconsin's Environment & Economy: Responding to Climate Change, promotes greater understanding of greenhouse gas mitigation and climate change impacts and adaptation. Dr. Gulledge also shares insights from a recently published Pew Center report, Regional Impacts of Climate Change, which addresses current and expected environmental effects and likely adaptation measures required in four U.S. regions.


Global Anthropogenic GHG Emissions by Gas

CO2 accounts for about 77 percent of total greenhouse gas emissions. Methane primarily from agriculture, contributes 15 percent of greenhouse gas emissions and nitrous oxide, mostly from industry and agriculture contributes 7 percent to global emissions.

Note: All figures here are expressed in CO2-equivalents.

Source: Climate Analysis Indicators Tool, World Resources Institute


Global Anthropogenic GHG Emissions by Sector

Globally, the primary sources of greenhouse gas emissions are electricity and heat (28%), agriculture (14%), transportation (12%), forestry (12%) and manufacturing (12%). Energy production of all types accounts for 65 percent of all emissions.

Source: Climate Analysis Indicators Tool, World Resources Institute


International Annual GHG Emissions

Most of the world's greenhouse gas (GHG) emissions come from a relatively small number of countries. China, the United States, and the 27 nations that make up the European Union (EU-27) are the three largest emitters on an absolute basis.

Sources: International Energy Agency, World Energy Outlook (2015)
                 International Energy Agency, CO2 Highlights (2015)
                 U.S. Environmental Protection Agency, International Non CO2 Projections (2015) 


Historical Global CO2 Emissions

Carbon dioxide emissions, primarily from the combustion of fossil fuels, have risen dramatically since the start of the industrial revolution.

Sources: Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory (2015)
                  International Energy Agency, World Energy Outlook (2015)

International Emissions

This section highlights trends in historic global emissions and shows emissions by gas and by sector. Other figures illustrate annual and cumulative emissions of key countries.

Click on the images below to view additional information on each figure.


Science & Impacts

The scientific community has reached a strong consensus regarding the science of global climate change. The world is undoubtedly warming, and the warming is largely the result of emissions of carbon dioxide and other greenhouse gases from human activities. Read More

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