Ask Jot

Chosen Answer by Dana1981

Interesting bit of cherrypicking, beginning the graph in 1960 instead of 1970, which changes the picture dramatically: http://www.bom.gov.au/cgi-bin/climate/change/trendmaps.cgi?map=rain&area=aus&season=0112&period=1970 This chart shows total annual rainfall, not the amount of drought. But more importantly, you're talking about a future prediction, and saying if drought has not increased (which you have not demonstrated) then it will not increase. A doesn't follow B. Plus as gcnp notes, the agricultural areas of Australia (which are rather small, as most of the country is desert) are indeed experiencing less annual rainfall. That's a tad of a problem.

Chosen Answer by Gwen

Had I gone for a masters degree in climate instead of archaeology, this would likely have been the direction my thesis would have taken. The guy says "Something is happening in Australia,". Well, no s--t. Due to its geographical location directly under the southern tropical belt, Australia is particularly prone to the influence of global warming. The global atmospheric circulation is accelerating because of the increase of energy in the earths systems due to GHGs. The tropical belts are expanding, which is causing a loss of agricultural land around the globe in areas neighbouring the subtropical high and Australia is directly under the subsiding air from the southern Hadley and Farrel cells. Until now they have been pretty well spared in the south as they have received adequate influence from the oceanic http://www.dpi.nsw.gov.au/__data/assets/pdf_file/0020/137225/air-masses-influencing-australian-weather.pdf air masses, but as the intensity of atmospheric circulation increases, it is creating higher pressures over the Australian continent and these maritime air masses will begin to have less and less influence thereby reducing the amount of rain the country receives. So the answer is yes, it really is a sign of things to come for nations bordering the subtropical highs. Let’s not forget that the United States is one of those countries and much of that nation’s food is grown in areas that will be affected. I’d like to add for anyone who reads this and doubts the impact that expanding subtropical highs can have on the planet, to take look at Google Earth and find them. It’s not hard lust look for the dry brown bits that make up the deserts that encircle the planet like the Sahara or Mojave. When you have found them ask yourself where the most populace countries are in relation to these belts and you will find that most of them such as China, India and United States all border these arid zones. Then remind yourself they are expanding and so far have expanded two degrees of latitude.