Climate Change refers to the overall warming of Earth’s atmosphere, water, and land, along with changes in sea level, weather patterns, and other indicators. It affects everything we depend on and value—including food, freshwater, wildlife, transportation, ecosystems, people’s health, and more.
Climate change is happening now. It’s the result of human activities, especially burning fossil fuels (coal, oil and natural gas) and deforestation. These activities increase the amount of heat-trapping greenhouse gases in the atmosphere, including carbon dioxide (CO2). The climate system is responding to these gases, warming the air and oceans. This is called the greenhouse effect. The global average surface temperature has increased by about 1.1 degrees Fahrenheit since the late 19th century.
Warmer oceans and warmer air mean higher temperatures and less snow and ice. This is a major problem for polar bears, marine life and many species that live in colder regions. It is also a problem for people living in coastal areas and islands that are vulnerable to rising sea levels. And warmer air means more severe storms, like the 2017 hurricanes that hit the US coasts.
A warmer atmosphere can hold more water vapor, which leads to increased rainfall. It can also make hurricanes and other storms stronger, and cause floods and erosion.
Across the world, rivers and lakes are drying up, glaciers and ice sheets are melting faster than ever before, and the geographic ranges of plants and animals are shifting. Climate change has also affected the frequency of wildfires, heat waves, and other extreme weather events.
These changes are expected to continue. And if we do not take immediate action, they could worsen. The UN’s climate body, the Intergovernmental Panel on Climate Change (IPCC), warns that if we fail to act quickly and do not limit temperature increases to 1.5 degrees Celsius above pre-industrial levels, several hundred million more people may be exposed to climate-related risks and susceptible to poverty by 2050.
We need to drastically cut our emissions of heat-trapping gases and remove them from the atmosphere. That will involve a huge shift away from fossil fuels and toward renewable energy sources. We must also reduce land-use practices that contribute to climate change, such as deforestation and overgrazing.
A wide variety of groups and individuals are working to address climate change. We’re mobilizing people and organizations to demand real solutions. This includes calling for climate-related investments in communities, cities and nations, and holding politicians accountable for their promises. And we’re urging people to support policy changes that will help slow and stop climate change, such as by putting a price on carbon pollution. We’re also pushing for more sustainable, equitable and resilient communities. And we’re urging governments to commit to a roadmap to net zero CO2 emissions by 2050. This will require a massive reduction in the use of coal, oil and gas. And it will mean keeping two-thirds of known fossil fuel reserves in the ground.