The Daily Parker

Politics, Weather, Photography, and the Dog

Three on climate change

Earlier this week, the Post reported on data that one of the scariest predictions of anthropogenic climate change theory seems to be coming true:

The new research, based on ocean measurements off the coast of East Antarctica, shows that melting Antarctic glaciers are indeed freshening the ocean around them. And this, in turn, is blocking a process in which cold and salty ocean water sinks below the sea surface in winter, forming “the densest water on the Earth,” in the words of study lead author Alessandro Silvano, a researcher with the University of Tasmania in Hobart.

In other words, the melting of Antarctica’s glaciers appears to be triggering a “feedback” loop in which that melting, through its effect on the oceans, triggers still more melting. The melting water stratifies the ocean column, with cold fresh water trapped at the surface and warmer water sitting below. Then, the lower layer melts glaciers and creates still more melt water — not to mention rising seas as glaciers lose mass.

"The idea is that this mechanism of rapid melting and warming of the ocean triggered sea level rise at other times, like the last glacial maximum, when we know rapid sea level rise was five meters per century,” Silvano said. “And we think this mechanism was the cause of rapid sea-level rise.”

Meanwhile, Chicago magazine speculates about what these changes will mean to our city in the next half-century:

Can Chicago really become a better, maybe even a far better, place while much of the world suffers the intensifying storms and droughts resulting from climate change? A growing consensus suggests the answer may be a cautious yes. For one, there’s Amir Jina, an economist at the University of Chicago who studies how global warming affects regional economies. In the simulations he ran, as temperatures rise, rainfall intensifies, and seas surge, Chicago fares better than many big U.S. cities because of its relative insulation from the worst ravages of heat, hurricanes, and loss of agriculture.

Indeed, the Great Lakes could be considered our greatest insurance against climate change. They contain 95 percent of North America’s supply of freshwater—and are protected by the Great Lakes Water Compact, which prohibits cities and towns outside the Great Lakes basin from tapping them. While aquifers elsewhere run dry, Chicago should stay flush for hundreds of years to come.

“We’re going to be like the Saudi Arabia of freshwater,” says David Archer, a professor of geophysical science at the University of Chicago. “This is one of the best places in the world to live out global warming.”

There’s just one problem: Water, which should be our salvation, could also do us in.

The first drops of the impending deluge have already fallen. Every one-degree rise in temperature increases the atmosphere’s capacity to hold water vapor by almost 4 percent. As a result, rain and snow come down with more force. Historically, there’s been a 4 percent chance of a storm occurring in any given year in Chicago that drops 5.88 inches of rain in 48 hours—a so-called 25-year storm. In the last decade alone, we have had one 25-year storm, plus a 50-year storm and, in 2011, a 100-year storm. In the best-case scenario, where carbon emissions stay relatively under control, we’re looking at a 25 percent increase in the number of days with extreme rainfall by the end of the century. The worst-case scenario sees a surge of 60 percent. Precipitation overall may increase by as much as 30 percent.

And in today's Times, Justin Gillis and Hal Harvey argue that cars are ruining our cities as well as our climate:

[T]he truth is that people who drive into a crowded city are imposing costs on others. They include not just reduced mobility for everyone and degraded public space, but serious health costs. Asthma attacks are set off by the tiny, invisible soot particles that cars emit. Recent research shows that a congestion charge in Stockholm reduced pollution and sharply cut asthma attacks in children.

The bottom line is that the decision to turn our public streets so completely over to the automobile, as sensible as it might have seemed decades ago, nearly wrecked the quality of life in our cities.

We are revealing no big secrets here. Urban planners have known all these things for decades. They have known that removing lanes to add bike paths and widen sidewalks can calm traffic, make a neighborhood more congenial — and, by the way, increase sales at businesses along that more pleasant street. They have known that imposing tolls with variable pricing can result in highway lanes that are rarely jammed.

We're adapting, slowly, to climate change. Over my lifetime I've seen the air in Chicago and L.A. get so much cleaner I can scarcely remember how bad it was growing up. (Old photos help.) But we're in for some pretty big changes in the next few years. I think Chicago will ultimately do just fine, except for being part of the world that has to adapt more dramatically than any time in the last few thousand years.

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