Is population growth a problem? THE problem?

Is a growing population at odds with a sustainable future? It's an old debate, and one that hasn't lost its power to arouse. Here's the latest iteration, with a letter in the New York Times entitled "Overpopulation is not the Problem." In it, geographer Erle Ellis concludes:

"There is no environmental reason for people to go hungry now or in the future. There is no need to use any more land to sustain humanity — increasing land productivity using existing technologies can boost global supplies and even leave more land for nature — a goal that is both more popular and more possible than ever. The only limits to creating a planet that future generations will be proud of are our imaginations and our social systems. In moving toward a better Anthropocene, the environment will be what we make it."


Of course, there are several letters in response, posted here. A trio of noted sustainability scholars (Clark, Schrag, and Cohen) responds: 

"Continued rapid human population growth makes it harder and more costly to solve all our problems. The institutional, technological and behavioral innovations that have a chance of leading to the rosy future Mr. Ellis envisions will happen only with substantial effort and investment, and will be easier with slower or no population growth."

More pithily, the UA's Alan Weisman replies that Ellis's assertion about no need for hunger
"must be comforting to the planet’s billion-plus hungry people."

More followup, including a deeper explanation of the author's perspective, is available on the Dot Earth blog here and here. 

What do YOU think?

Why has average global temperature flattened out?

Some of you may have noticed that global temperatures appear to have stopped increasing over the last decade or so. The Yale Forum on Climate and the Media has a good summary post as to why:

http://www.yaleclimatemediaforum.org/2013/09/examining-the-recent-slow-down-in-global-warming/

The article breaks down "global" temperature into its components - like land surface temperature, ocean surface temperature, and shows the data and temperature trends for each component. It also investigates natural variability in the climate system that could be contributing to the recent flatness.

Basically, natural variability is masking a lot of the human-caused change over the past decade. There's more to it than that, including things we'll talk about like other places that are taking up the heat (like the deep ocean), but that's one piece of the puzzle. The article is a little dense with info, but if you're interested, check it out!