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Life is change … or is it?

September 21, 2011 | 1:23 pm | , Science and Solutions Director

© 2009 Flickr / Matt MacGillivray cc by 2.0

There’s an old saying that goes: “The only thing constant in life is change.” Because living things already cope with an ever-changing world, it’s easy to think they can handle human-made climate change as well. But as one of our readers recently noted, the rate of climate change poses a new challenge to species.

Earth has warmed, on average, by about 0.8 degrees Celsius since 1880 — about 10 times faster than in the last 21,000 years. About two thirds of that warming has taken place since just 1975, with the biggest changes near the poles.

Of course, plants and animals (including people) don’t experience global change — they experience local and regional change. Take for example, the western Antarctic Peninsula, one of the fastest warming parts of the planet. Spiking temperatures have opened up previously inhospitable Antarctic waters to king crabs. Early evidence suggests the skeleton-crushing crabs are depleting native animals like starfish and sea urchins.

Now zip around the world to North America’s boreal forest, a vast ecosystem that provides breeding habitat to nearly half the birds in the U.S. and Canada. Rapid warming has shortened the snow cover season in the western boreal by an average of 11 days since 1973 . Earlier snowmelt changes the timing of ice breakup on lakes, and consequently may change the timing of peak food abundance for ducks. It seems that some species of ducks, like white-winged scoters, are declining as a result. Scoters have a short, inflexible breeding season, making it difficult for these ducks to produce chicks if there’s a change in the timing of their food supply.

White-winged scoters are common across North America, but population declines of up to 50% in recent decades have caught the attention of scientists. Climate is not the only reason for the declines; scoters are also affected by stresses like oil spills and fishing nets. This raises another important point about why living things will have a hard time adapting to climate change. The climate is not only changing extremely quickly — it is also accompanied by an unprecedented array of other human activities that degrade the health of natural systems.

Across the U.S. and Canada, bird watchers, hunters and anglers, and parents who take their kids to the park are all seeing the reality of climate change. Add your voice to theirs — leave us a comment about changes you’ve seen in your local plant and animal life.

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