Global Warming and Global Climate Change

The world’s leading scientists agree that the planet is warming and that human activities—especially the burning of fossil fuels and the clearing of forests—are a big part of the cause.

In a 2007 report, the Intergovernmental Panel on Climate Change, the international group of scientists charged with reviewing, validating and summarizing the latest research concluded that the warming of the climate system is unequivocal. They stated that it is 90 percent certain that human-generated greenhouse gases account for most of the warming in the past 50 years.

Many published scientific reports have documented the actual observed impacts of a warming planet—including dramatic melting of the Arctic ice cap, shifting wildlife habitats, increased evidence of wildfires, heat waves and more intense storms. Americans are now seeing the impacts of global warming in their backyards. The warming trend poses serious risks to the economy and the environment.

Pew uses two approaches to address climate change: science and policy analysis and advocacy campaigns.

• The Pew Center on Global Climate Change is a leading policy and research institute. It advances debate through analysis, public education and a cooperative approach with business. The center launched in 1998.
• The Pew Campaign on Global Warming is aimed at adoption of a national policy to reduce emissions throughout the economy, and the Pew Campaign for Fuel Efficiency seeks more stringent fuel efficiency standards for the nation’s cars and trucks.

Achieving the large-scale reductions in emissions needed to address climate change will require a major shift in the way the world produces and uses energy. Yet it can be done. While this change will not be easy, deploying currently available technologies could sufficiently reduce emissions over the next 50 years to avoid the most dangerous threats from global warming.

The urgency of addressing climate change is prompting policy makers throughout the world to take action to reduce global warming pollution. In the United States, cities, states and the private sector are leading the way and, after years of inaction, even Congress is beginning to make global warming a priority.

No global strategy to address climate change can succeed without substantial, permanent and mandated reductions in U.S. emissions. Leadership by the United States—still the world’s largest per capita emitter of global warming pollution—is vital to solving the most significant environmental challenge of our time.

An immediate step needed is the establishment of mandatory emission limits, coupled with a market-based system that allows reductions to be achieved as cost-effectively as possible. Complementary energy policies must also be enacted quickly, including more stringent fuel efficiency standards for vehicles, a national renewable energy standard, energy efficiency measures, and other short- and long-term strategies to speed the transition to low- and zero-emission technologies.