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The world is turning into a desert. Run for the hills!
"Desertification is a fancy word for land that is turning to desert," begins Allan Savory in this quietly powerful talk. And terrifyingly, it's happening to about two-thirds of the world's grasslands, accelerating climate change and causing traditional grazing societies to descend into social chaos." https://m.youtube.com/watch?v=vpTHi7O66pI Back on planet Earth, a review of the current scientific literature would appear to disprove this thesis. IF the Sahara desert is expanding, it is a local issue. Elsewhere, the deserts are retreating and on average the trend is to global greening. E.g. Greening of the globe and its drivers - Nature 2016 https://www.nature.com/articles/nclimate3004
"Satellite records from 1982–2009 show a persistent and widespread increase of leaf area (greening) over 25% to 50% of the global vegetated area, whereas less than 4% of the globe shows decreasing leaf area (browning).
Ecosystem models suggest that CO2 fertilisation effects explain 70% of the observed greening trend, followed by nitrogen deposition (9%), climate change (8%) and land cover change (4%)." Elevated CO2 as a driver of global dryland greening - Nature 2016 https://www.nature.com/articles/srep20716
"Recent regional scale analyses using satellite based vegetation indices such as the Normalized Difference Vegetation Index (NDVI), have found extensive areas of “greening” in dryland areas of the Mediterranean, the Sahel, the Middle East and Northern China, as well as greening trends in Mongolia and South America. More recently, a global synthesis from 1982-2007 showed an overall “greening-up” trend over the Sahel belt, Mediterranean basin, China-Mongolia region and the drylands of South America." Global Greening Is Firm, Drivers Are Mixed - Harvard 2014 http://adsabs.harvard.edu/abs/2015AGUFM.B31A0515K
"Evidence for global greening is converging, asserting an increase in CO2 uptake and biomass of the terrestrial biosphere.
Global greening refers to global net increases in the area of green canopy, stocks of carbon, and the duration of the growing season.
The growing seasons in general have prolonged while the stock of biomass carbon has increased and the rate of deforestation has decelerated.
Evidence for these trends comes from firm empirical data obtained through atmospheric CO2 observations, remote sensing, forest inventories and land use statistics." Rise in CO2 has 'greened Planet Earth'
http://www.bbc.co.uk/news/science-environment-36130346
Prof Judith Curry, the former chair of Earth and atmospheric sciences at the Georgia Institute of Technology, added: "It is inappropriate to dismiss the arguments of the so-called contrarians, since their disagreement with the consensus reflects conflicts of values and a preference for the empirical (i.e. what has been observed) versus the hypothetical (i.e. what is projected from climate models). I hope all you empiricists will join me in celebrating this good news. Cheers! |
Carbon Dioxide Fertilization Greening Earth, Study Finds - https://www.nasa.gov/feature/goddard/2016/carbon-dioxide-fer...
While it sounds like good news for the ecology, I think the overall destructive effects of human activity on the global environment far outweighs any accidentally beneficial effect of rising CO2. Celebrating it as "global greening" seems to be just as much of an oversimplification as the fear-mongering of desertification.