Friday, October 21, 2016

Matt Ridley: Global Warming versus Global Greening

Matt Ridley: Global Warming versus Global Greening | The Global Warming Policy Forum (GWPF)

"...After covering global warming debates as a journalist on and off for almost 30 years, with initial credulity, then growing skepticism, I have come to the conclusion that the risk of dangerous global warming, now and in the future, has been greatly exaggerated while the policies enacted to mitigate the risk have done more harm than good, both economically and environmentally, and will continue to do so.
And I am treated as some kind of pariah for coming to this conclusion.
Why do I think the risk from global warming is being exaggerated? 
For four principal reasons.
1. All environmental predictions of doom always are;
2. the models have been consistently wrong for more than 30 years;
3. the best evidence indicates that climate sensitivity is relatively low;
4. the climate science establishment has a vested interest in alarm.

Global greening

I will come to those four points in a moment. But first I want to talk about global greening, the gradual, but large, increase in green vegetation on the planet.
I think this is one of the most momentous discoveries of recent years and one that transforms the scientific background to climate policy, though you would never know it from the way it has been reported. And it is a story in which I have been both vilified and vindicated.
In December 2012, the environmental scientist Jesse Ausubel of Rockefeller University drew my attention to a video online of a lecture given by Ranga Myneni of Boston University.
In this lecture Myneni presented ingenious analysis of data from satellites proving that much of the vegetated area of the planet was getting greener, only a little bit was getting browner, and that overall in 30 years there had been a roughly 14% increase in green vegetation on planet Earth.

In this slide he argued that this was occurring in all vegetation types – tropical rain forests, subarctic taiga, grasslands, semi-deserts, farmland, everywhere.
What is more, Myneni argued that by various means he could calculate that about half of this greening was a direct result of rising carbon dioxide levels in the atmosphere, rather than the application of agricultural fertiliser, irrigation, warmer temperatures or increased rainfall.
Carbon dioxide, along with water, is the raw material that plants use to make carbohydrates, with the help of sunlight, so it stands to reason that raising its concentration should help plants grow.
I was startled by Myneni’s data. I knew that there had been thousands of so-called free-air concentration (FACE) experiments, in which levels of CO2 had been increased over crops or wild ecosystems to find out if it boosted their growth (it did), and that commercial greenhouse owners now routinely maintain CO2 levels in their greenhouses at more than double ambient levels – because it makes their tomatoes grow faster.
But the global effect of CO2 levels on the quantity of vegetation had not, as far as I could tell, been measured till now.
Other lines of evidence also pointed to this global greening:
* the increased rate of growth of forest trees,
* the increased amplitude of seasonal carbon dioxide variation measured in Hawaii and elsewhere,
* photographic surveys of vegetation,
* the increased growth rate of phytoplankton, marine plants and some corals, and so on.
I published an article in the Wall Street Journal in January 2013 on these various lines of evidence, including Myneni’s satellite analysis, pointing to the increase in green vegetation.

This was probably the very first article in the mainstream media on the satellite evidence for global greening..."
Lots here.
Read on!

No comments: