How the new world of climate change and disruption of nature is challenging the American spirit

David Wolfe, professor of plant ecology in the Department of Horticulture, is a leading authority on the effects of climate change and rising atmospheric carbon dioxide on plants, soils and ecosystems. He is currently working with the Union of Concerned Scientists and a team of experts in the Northeast on a regional climate change impacts assessment. This is the second in a regular column of ideas and opinion. Submissions are invited.

It is a cold, snowy day in April as I write this. A little global warming sounds appealing at times like this, but we should be careful what we wish for. Warmer winters are predicted to increase lake-effect snows, for example, because the warmer lakes will evaporate more moisture into the atmosphere. We have created a new world where we can no longer rely on historical weather records to tell us what to expect; they only tell us how far from "normal" we have strayed.

It is true that the Earth's climate is always changing, but seldom has it been warmer than it is today, and seldom has the pace of change been this fast. To put things into context, during the past 10,000 years the Earth warmed by about 11 degrees, causing a gradual melting of the glacial ice sheet that once covered the Northeast. Now, climate models project that within this century alone, our region will warm by another 7 to 12 degrees in a "business as usual" scenario of greenhouse gas emissions.

Evidence of accelerated climate change also can be observed in the living world. Here in the Northeast, several collaborators and I documented an advance in spring bloom dates of four to eight days since the 1960s for lilacs, grapes and apples. Meanwhile, Cornell integrated pest management specialists have found they must begin monitoring certain crop insects several weeks earlier than they used to. With winters warming in our region by more than four degrees since 1970, there is a very real threat of increased pressure from marginally overwintering crop pests. Throughout the Northern Hemisphere earlier spring arrival of migrating birds, northward expansion of habitat range for invasive species and other indicators of change are being reported.

What worries me and other ecologists the most is the disruption of important interactions between species. For example, if a plant is blooming earlier, will the pollinators show up earlier too? If a bird nests earlier, will the caterpillars it feeds its young be there when they hatch? Climate zones are shifting northward, but we will never see an entire complex community of species migrate northward en masse. Disruption of species interactions could impair the functioning of ecosystems that provide us with clean water, food and other human needs.

It is not just ecologists and "nature lovers" who are worried about climate change. For example, I recently spoke at a climate symposium held near Albany attended by more that 400 city and regional planners concerned about the increase in flood damage to homes and infrastructure along the Hudson River in recent years. A 15-inch rise in sea level at New York Harbor and increased frequency of heavy rainfall events associated with climate change contribute to the problem. Citizens can't afford the flood insurance, and city planners must make decisions regarding shoreline zoning and the capacity of storm-drainage systems. For farmers the issue is more frequent flood damage to crops. Climate projections for the region indicate not only a continuation of this problem, but also an increase in short-term droughts as more late summer rainfall is concentrated into heavy downpours.

Sea level rise and increased flooding risk are worldwide problems that could be particularly devastating for heavily populated low-lying areas in such poor nations as Bangladesh. (Not that the United States demonstrated good coping skills with Katrina). Projections for severe droughts and heat stress are the concern for sub-Saharan Africa. In a global economy we will not be insulated from disasters elsewhere. A recent study commissioned by the U.S. Center for Naval Analyses concluded climate change poses risks to national security and documented the potential for international conflicts over water, food, borders and environmental refugees.

The goal of our research and education outreach program at Cornell is to provide decision makers, from policy-makers to farmers and gardeners, with information to take advantage of opportunities (e.g., new crops for longer growing seasons) and minimize risks associated with climate change. In this way we might adapt, or "manage the unavoidable," as a recent United Nations report phrased it.

We also need to mitigate greenhouse gas emissions -- "avoid the unmanageable." At long last it seems we may have turned a corner regarding our motivation for action. Perhaps it is the evidence of climate change in our own backyards, the near consensus among the scientific community, Al Gore's movie or some combination. In any case, there are many positive signs -- such as President David Skorton signing a commitment to improve Cornell's energy efficiency. Corporations and entrepreneurs are seeing the profit potential of going green. That is the American spirit I grew up with.

No nation in the world so thrives on challenge as ours, and we've created a real doozy for ourselves with this one. Our climate has moved beyond "normal." The question now is -- how far are we willing to let it go?

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