Has Plant Life Reached Its Limits?

hessian writes with this news from the New York Times: "Since 2000, Dr. [Steven] Running and his colleagues have monitored how much plant growth covers terra firma, using two NASA satellites in the agency's Earth Observing System. After they crunched the numbers, combining the current monitoring system's data with satellite observations dating back to 1982, they noticed that terrestrial plant growth, also known as net primary production, remained relatively constant. Over the course of three decades, the observed plant growth on dry land has been about 53.6 petagrams of carbon each year, Dr. Running writes in the article. This suggests that plants' overall productivity — including the corn that humans grow and the trees people log for paper products — is changing little now, no matter how mankind tries to boost it, he said."

Comments

But are we really trying?

[__aaltlg1547]

What we're trying to do is grow SPECIFIC plants that are useful to people. We have never cared much if at all that what we are really doing is converting areas that grow one kind of plant to grow another kind of plant. If we were trying to increase primary production, no doubt we could do that, but we would be up against the same things that limit agriculture now: mainly water availability. But if you built a lot of greenhouses and water recycling systems we could probably increase primary production substantially.

Re:But are we really trying?

[icebike]

What we're trying to do is grow SPECIFIC plants that are useful to people. We have never cared much if at all that what we are really doing is converting areas that grow one kind of plant to grow another kind of plant. If we were trying to increase primary production, no doubt we could do that, but we would be up against the same things that limit agriculture now: mainly water availability. But if you built a lot of greenhouses and water recycling systems we could probably increase primary production substantially.

Well, that's a nice theory, but its simply not true.

The amount of land dedicated to farming has not substantially increased, (in fact it has decreased) as farming becomes more efficient. Vast tracts of the
midwest have returned to forest because there is simply no economic need to keep these lands under the plow.

This whole theory is nothing but a huge rehash of the Limits To Growth, cited in TFA. Yet 40 years hence, LTG has been proven wrong in just about every single prediction they made. Their methodology and assumptions were simply wrong.

Measurement of plant tonnage via satellite imagery has revealed that plants still grow just about everywhere they ever did. Wow. Major revelation.

Yet the satellites seem to miss the fact that global food production has more than tripled since 1961, and worldwide, we are only using 7% more land in the process. In North America Europe, and Russia, we are actually cultivating less land, and producing vastly more food. Marginal lands have fallen fallow, and returned to prairie or forest of a 2 hundred years ago.

Measuring the area covered by plants says nothing about the tonnage harvested every year off of that land. Nor does it say anything about the reduced pollution produced in the process, and the return of natural flora coverage. The total forest area in the U.S. has been relatively stable for the last 100 years (currently about 747 million acres). The species may change (they always have over time). But its not because we have converted the land to farming. For the last 100 years, the biggest threat to forests has been housing development, not farming.

Or, another way to look at it...

[EmagGeek]

... no matter how much plant matter humans harvest for various reasons, the Earth is able to replenish it to its maximum level.