Climate Change
Coral reef, © Jim Maragos/USFWS
Polar bear, © Tom Schneider

Climate Change 101

Climate change occurs as increased amounts of gases in the atmosphere allow the sun’s light to reach the Earth, but trap its heat radiating back from the surface.  Because the effect is similar to the way that the inside of a car or a greenhouse heats up on a sunny day, these gases are sometimes referred to as “greenhouse gases.” The most important greenhouse gas is carbon dioxide, emitted by the burning of fossil fuels  and the clearing of forests.

The biggest effect of this greenhouse gas pollution is the warming of the planet. The average temperature of the globe has risen 1.3 degrees F since the turn of the last century.  After decades of conclusive scientific research, we know now that the effect of human-caused emissions on the climate is unmistakable — the changes we have seen in this time period are far beyond what a natural climate shift would produce. And projections for the future indicate that unless we reduce the rate of greenhouse gas emissions, we could be headed for a 5-10 degree F rise by 2100.

Already, climate change is causing plenty of problems for people. Extreme weather events like heat waves, storms and droughts are on the rise, causing billions of dollars’ worth of damage each year. But just as worrisome are the impacts to wildlife and the habitats on which they depend.

How Climate Change Affects Wildlife

Many people know that climate change is causing Arctic sea ice to melt, which in turn threatens polar bears who need the ice to hunt for their prey. But the Arctic is hardly alone in feeling the heat. Droughts caused by changes in rain patterns reduce desert grasses and flowering plants that other animals depend on, like the critically endangered Sonoran pronghorn. And shorter winters increase the amount of time pests have to grow and multiply, like the pine bark beetle that is devastating forests all over North America. Many types of habitat are expected to shift, shrink, or even blink out entirely in the face of warmer temperatures, changes in the growing season, and an increase in long droughts interrupted with intense rainfall.

And the problems aren’t just on land. Warmer ocean waters can kill coral reefs, which countless marine species depend on for food and shelter. Changes in ocean currents are shifting the location of prime feeding grounds farther from islands where certain seabirds have nested for centuries.   And some of the carbon dioxide we emit naturally dissolves in the ocean, where it forms an acid strong enough to dissolve the shells of some marine organisms.

Because of the wide variety of impacts it has on the environment, climate change is now one of the leading threats to wildlife and habitats.

What Defenders Is Doing to Help Wildlife Threatened by Climate Change

Climate change is a massive problem that needs to be tackled on multiple fronts. Defenders is working to ensure the best science is being used to understand the full impacts of climate change on wildlife and ecosystems. We are a leader in the conservation community when it comes to advocating for laws, policies and funding to help combat the threat. And we’re also devising strategies and guidelines to help wildlife and natural resource managers prepare for the impacts of climate change.

You’ll find more details about our efforts on climate change throughout our website because it is related to virtually every aspect of what we do. Many of our wildlife pages include details about how climate change specifically affects animals like polar bears and sea turtles. Our Habitat Conservation section discusses its impact on areas like wildlife refuges and national forests. And our work to help develop “smart from the start” strategies for renewable energy development is critically important to helping solve this global problem.

More on Climate Change: Impacts of Climate Change »

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