Contrary to popular belief – the effects of moderate global warming may not be all bad. For the first time ever, a four year U.S. national assessment has examined the regional impacts of global warming revealing everything from potentially severe droughts to larger crop yields for some farmers.

The report, Climate Changes in the United States, predicts that as greenhouse gases continue to rise at their current rates and trigger extreme climate changes, average temperatures in the U.S. may rise 5 to 10 degrees Fahrenheit in the next century.

The report’s agricultural section projects yield increases for crops such as wheat, barley and most vegetables in regions like the northern plains. But on the downside, this would mean using more pesticides and an increase in the threat of nitrogen-fertilizer runoff into bays. And yes, on a positive note, the warming may take some of the chill out of winter in some areas, but when temperatures rise in the summer, the warming may lure disease-bearing mosquitoes and other animal sources of disease.

University of Toronto geography professor Danny Harvey says some of the report’s more positive projections should not detract from the many potential dangers of global warming. “A small amount of warming could have positive effects, but if we don’t take preventative action then we will end up not with a small amount of warming but a large amount of warming,” says Harvey. “A one or two degree of warming may have positive impacts in some areas but, a five to seven degree of warming could have very negative impacts.”

The report used computer climate models to predict the profound changes that may greatly transform regions, like the threat of drought in the Southeast and increased rainfall in parched areas of the Southwest. But some critics believe that computer models cannot accurately predict the impact of global warming on a regional basis.

Harvey thinks that these skeptics are missing the larger issue. “The things we’re most concerned about depend on very basic fundamental principals,” says Harvey. “We can say that drought risk will increase in the interior of continents and that does not depend on the details of any models. The point is that there is an overall risk.”

Although the U.S. report was the first that examined American regions on an in-depth scale, Environment Canada has been examining the regional impact of global warming for some time. Recent study by Canada Country Study (CCS) revealed many possible global warming consequences for Canada, including floods and droughts in southern British Columbia and coastal erosion in the Atlantic region. The six part national assessment examined the impacts of climate change on Canada as a whole and suggested modes of action as well as issues that need further research.

Roger Street, director of the adaptation and impacts research group for Environment Canada, says both the positive and negative issues that were uncovered in the Canadian study have to be put into context. “Having temperatures warm up in the winter cannot be all negative but even from this perspective we have to understand what could be positive for one community may be negative for another,” says Street, the study’s lead coordinator. “Warmer winters might be good for some but what happens to those communities that rely on snowfall or winter recreation?”

Street adds that many of the regional effects that are projected in the U.S. report were also stated in the CCS – one of the main concerns being a fresh water shortage. Both assessments also project that rain will fall heavily in some regions followed by long dry spells, bringing about flash flood weather patterns.

Street says that one of our hopes for dealing with global warming in Canada lies in the rate at which it is happening. “The slower the rate of change occurs and the less the rate of change occurs the more chance we have to adapt and develop coping technologies,” says Street. “Slow change will allow natural systems and human activities to adapt to changes.”