Climate warming could cause Florida to be invaded by new tropical species.© Getty

Climate warming is influencing the lifestyles of animals and plants right across the United States, a report has warned. The changes are bringing rival species into contact with each other and could upset entire ecosystems.

Over the past few decades many plants have begun flowering earlier in spring in response to rising temperatures, and animals have migrated north or moved to higher altitudes, reports Camille Parmesan of the University of Texas at Austin, one of the report's authors.

One example is the red fox (Vulpes vulpes), which is already widespread across North America but is now pushing north, threatening the weaker Arctic fox (Alopex lagopus), says Parmesan. Other more subtle effects may occur as, for example, birds altering the timing of their arrival at breeding grounds find themselves with less food or space.

The report¹, published by the Pew Center on Global Climate Change in Arlington, Virginia, collates data from 40 ecological studies spanning anything from 20 to 100 years. The effects of climate warming were visible in around half of the studies that the report's authors examined.

"The message is that human-driven climate change has affected species all across the United States, from new tropical species arriving in Florida to changes in the basic functioning of ecosystems in Alaska," says Parmesan.

Hard to adapt

The greater the rate of climate warming, the smaller the number of species that will be able to adapt without disrupting their lifestyles or ecosystems. Climate experts point out that some parts of Alaska warmed by 4°C during the twentieth century, compared with a global average of around 0.6°C. And they fear that warming could accelerate if greenhouse-gas emissions are remain unchecked.

"With warming for the next century projected to be two to ten times greater than the last, we're heading towards a fundamental and potentially irreversible disruption of the US landscape and wildlife," warns Eileen Claussen, president of the Pew Center.

Environmentalists hope that the report will spur efforts to beat climate change in the United States, which in 2001 pulled out of the Kyoto treaty, an agreement now given fresh power by its ratification by Russia.

"The international community is taking steps," Benjamin Preston, an environmental researcher at the Pew Center, told news@nature.com. "People in the US need to ask: when is the proper time to respond? The proper time is now." 

University of Texas, Austin

Pew Center on Global Climate Change

• References

  1. Parmesan C. & Galbraith H. Pew Cen. Clim. Change, http://www.pewclimate.org/docUploads/final%5FObsImpact%2Epdf (2004).