Thursday, January 31, 2013

The Greening of the Globe

The Earth is getting greener. From Matt Ridley's blog:
Did you know that the Earth is getting greener, quite literally? Satellites are now confirming that the amount of green vegetation on the planet has been increasing for three decades. This will be news to those accustomed to alarming tales about deforestation, overdevelopment and ecosystem destruction.

This possibility was first suspected in 1985 by Charles Keeling, the scientist whose meticulous record of the content of the air atop Mauna Loa in Hawaii first alerted the world to the increasing concentration of carbon dioxide in the atmosphere. Mr. Keeling's famous curve showed not only a year-by-year increase in carbon dioxide levels but a season-by-season oscillation in the concentration.

During summers in the Northern Hemisphere, the Earth breathes in carbon dioxide as green plants (most of which are north of the equator) absorb the gas and turn it into carbohydrate. In the northern winter, the Earth breathes the gas out again, as the summer's leaves rot.

Mr. Keeling and colleagues noticed that the depth of the breathing had increased in Hawaii by 20% [by 1995] since the 1960s: The Earth was taking in more carbon dioxide each northern summer and giving out more each winter. Since the inhalation is done by green leaves, they reasoned, the amount of greenery on the planet must be growing larger. In the 1980s forest biologists started to report striking increases in the growth rates of trees and the density of forests: in Douglas firs in British Columbia, Scots pines in Finland, bristlecone pines in Colorado and even tropical rain forests.

Around the same time, a NASA scientist named Compton Tucker found that he could map global vegetation changes by calculating a "Normalized Difference Vegetation Index" (NDVI) from the data produced by a satellite sensor. The data confirmed Mr. Keeling's suspicion: Greenery was on the increase. At first, this was thought to be a northern phenomenon, caused by faster growth in the great spruce and birch forests of Siberia and Canada, but the satellites showed it was happening all over the world and especially strongly in the Amazon and African rain forests. Using the NDVI, one team this year reported that "over the last few decades of the 20th century, terrestrial ecosystems acted as net carbon sinks," i.e., they absorbed more carbon than they were emitting, and "net greening was reported in all biomes," though the effect had slowed down in recent years.
(Underline added).

I've noted before that there are several questions that need to be answered before hobbling our economies to stop global warming:

1.  Is there an increase in global temperature due to increased CO2?
2.  Is the increase in CO2 due to human activity?
3.  Is the increase in CO2 and/or global temperature overall detrimental?
4.  Is there anything we can do to stop or reverse the trend?

It is not clear that there has been sustained global warming over the past 100 years, and it appears to have stopped nearly a decade ago. We know that there has been a lot of bad science and active deception by those claiming that there is global warming. There is reasonable doubt that temperatures increase are due to human activity. The harm seems to be assumed--the Earth has been as warm or warmer in the past. In short, none of the questions have been satisfactorily answered in the affirmative.

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