Despite Growing Impacts of Global Warming, Legislation Blocked in Congress

Kittlitz's Murrelet in Flight. Photo: USGS

Climate change caused by the growing CO2 concentration in the atmosphere is magnifying the impact that stresses such as pollution and habitat destruction are having on ecosystems through higher temperatures, reduced water availability, and increased frequency of heavy precipitation events and severe storms. For example, higher minimum temperatures and warmer springs extend the range and lifetime of many pests that stress trees and crops. It also extends the fire season, which is now arriving approximately one month earlier and lasting one month longer than in the recent past.

These are some of the findings in a new U.S. Environmental Protection Agency (EPA) report that reviews the impacts of global warming on a variety of ecosystems in the United States, including estuaries, forests, and wetlands. The report, Preliminary Review of Adaptation Options for Climate-Sensitive Ecosystems and Resources, also identifies strategies that may help land managers reduce these impacts.

Climate change is already having negative consequences for many species of plants and animals, including birds. Studies are finding that the range of many species is shifting poleward and to higher altitudes. At least seven North American warbler species (Prothonotary, Blue-winged, Golden-winged, Black-throated Gray, Pine, Hooded, and Cape May Warblers) are documented to have shifted their range north in the past 24 years, by an average of more than 65 miles.

Similarly, the timing of migration is also shifting for some species. A recent Boston University study found that eight out of 32 migratory bird species are arriving in Massachusetts significantly earlier than in 1970. The study concluded that birds with the shortest migration routes have adapted best to the warming, while birds with longer migration routes, such as those wintering in South America, have not yet altered the timing of their migrations. This is of great concern because these species may be imperiled if the food sources that the birds depend on when they arrive at their breeding destination have changed.

A recent study published in The Auk has found an 83% population decline of the critically endangered Kittlitz’s Murrelet in Glacier Bay, Alaska between 1991 and 2000. A study of the species in Alaska’s Prince William Sound found similar declines of 84%. Retreating glaciers upon which the birds nest is the likely cause.

The EPA report recommends continuing current best management practices, because they are often what are also needed to reduce the impacts of climate change. A good example is the creation of stream buffers, which create important riparian habitat while reducing polluted runoff into streams, and mitigate the impacts of flooding caused by extreme weather events which are increasing due to global warming.

The report also encourages reducing human impacts such as habitat fragmentation, comprehensive habitat protection where there is adequate representation of all types of different ecosystems and replication so that there is more than one example of each protected habitat type, and the creation of protected reserves to serve as destinations for climate-sensitive migrants. One of the greatest challenges facing land managers will be to provide habitat linkages and migration corridors to allow for the movement of wildlife as the climate shifts.

Despite these growing impacts and the need for immediate action, enough Senators chose to filibuster legislation that would begin to reduce CO2 emissions, ensuring that there will be no bill passed to address this threat this year. The Lieberman-Warner Climate Security Act, which creates a cap-and-trade system to limit CO2 emissions and provides funding to help impacted wildlife species, received support from a majority of Senators (48 voted in favor and six Senators who were not present issued statements of support), but fell well short of the 60 votes needed to end the filibuster.

For more information about the impacts of global warming on birds, please see American Bird Conservancy’s factsheet.