U.N. scientists to policymakers: Prepare for climate change now

In a report for policymakers, released today in Kampala, Uganda, the U.N. Intergovernmental Panel on Climate Change calls for countries to prepare for the growing risk of extreme weather around the world.

“The report gives differing probabilities for extreme weather events based on future greenhouse gas emissions scenarios, but the thrust is that extreme weather is likely to increase,” Reuters reports.

Think heat waves, more powerful hurricanes and typhoons.

Over at Dot Earth, the New York Times’ Andrew Revkin has pulled the report’s key findings about climate change’s predicted humanitarian effects. Here are some of the more startling forecasts:

—It is virtually certain that increases in the frequency of warm daily temperature extremes and decreases in cold extremes will occur throughout the 21st century on a global scale. It is very likely— 90 percent to 100 percent probability—that heat waves will increase in length, frequency and/or intensity over most land areas.

—It is likely that the average maximum wind speed of tropical cyclones (also known as typhoons or hurricanes) will increase throughout the coming century, although possibly not in every ocean basin. However it is also likely—in other words there is a 66 percent to 100 percent probability — that overall there will be either a decrease or essentially no change in the number of tropical cyclones.

—There is evidence, providing a basis for medium confidence, that droughts will intensify over the coming century in southern Europe and the Mediterranean region, central Europe, central North America, Central America and Mexico, northeast Brazil, and southern Africa. Confidence is limited because of definitional issues regarding how to classify and measure a drought, a lack of observational data and the inability of models to include all the factors that influence droughts.

—Projected precipitation and temperature changes imply changes in floods, although overall there is low confidence at the global scale regarding climate-driven changes in magnitude or frequency of river-related flooding, due to limited evidence and because the causes of regional changes are complex.

And here’s a presentation of the report:

But what does it all mean for human health?

“We need to be worried,” Maarten van Aalst, a lead author of the report, told the Associated Press. “And our response needs to anticipate disasters and reduce risk before they happen rather than wait until after they happen and clean up afterward. … Risk has already increased dramatically,” said van Aalst, who is the director of the International Red Cross/Red Crescent Climate Centre in the Netherlands.

The problem — especially from a global development perspective – is that the risk is also unequal, “not just in that sense (of impacts), but also in the sense of ability to project future risk,” van Aalst told AlertNet. So it’s difficult to prepare as well in lesser developed nations. “We have much better data for Western Europe and North America than we have for most of Africa,” he said.

And indeed when it comes to the health impact of climate change, Humanosphere readers know there is cause for concern. Climatide’s Heather Goldstone has also broken down why ocean warming could harm health.

But as we head toward a seemingly inevitable increase in at least some types of natural disasters, we might find some surprising health effects. Remember images like this one of “spiderweb trees”  from Pakistan?

Flickr, DFID – UK Department for International Development

Those trees, which were an unexpected result of the 2010 flooding in Pakistan, actually may help with malaria prevention. New Scientist explains:

Although slowly killing the trees, the phenomenon is seemingly helping the local population. People in Sindh have reported fewer mosquitos than they would have expected given the amount of stagnant water in the area. It is thought the mosquitoes are getting caught in the spiders’ webs, reducing their numbers and the associated risk of malaria.

This isn’t to suggest that climate change is actually a net positive when it comes to human health. Most of the evidence doesn’t suggest that. But, when it comes to local effects, it’s more complicated than a simple “good” or “bad” judgment. Bottom line: it’s not called climate change for nothing.

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