The followers of this blog should be well ahead of the rest of the internet regarding the current extreme weather in America if they read Mark Cochrane’s guest post way back in July last year titled “Weather Whiplash”.
Of course, all the climate deniers are out in force these last few days, letting themselves believe that the snowball weather in the US is proof “climate change is crap”……. when in fact, nothing of the sort is true. As counterintuitive as it may seem, global warming is causing the polar ice to melt, and that melting is sending the weather haywire by making the jetstream do things it was never meant to do.
The dramatic melt-off of the Arctic sea ice due to climate change, is hitting closer to home for millions of Americans. That’s because melting Arctic sea ice has triggered a domino effect leading to increased odds of severe winter weather events in the Northern Hemisphere’s mid latitudes — think “The Day After Tomorrow”. Well, metaphorically anyway….. though who knowswhat the future may hold on that front!
Australians may think of Arctic climate change as this remote phenomenon that has little effect on our everyday lives, but what goes on in the Arctic remotely forces weather patterns, even here in Australia….. What drives the weather is energy. Heat energy to be precise. At any one time, there is a precise amount of energy in the Earth’s atmosphere. It is growing, apparently at the rate of four Hiroshima bombs per second, but even at such a mindboggling rate, over short periods like a week or a month, it may as well be constant, so able is the planet’s capacity to absorb it.
The Earth’s spin sends eddies in both the air and oceans, causing turbulence in the way this energy is distributed or moved about the biosphere. Heat normally wants to travel towards cold places and equalise the temperature of cold areas and hot areas. But these eddies don’t allow the heat to travel in a straight line, as it would in, say, a piece of metal heated at one end. Solar energy creates wind this way, and these eddies cause the wind to move along curved paths, as do ocean currents.
Add energy into the system by trapping heat under the blanket of greenhouse gases, and the eddies become more energetic. A bit like when you heat a saucepan of water; the water molecules become more and more energised, start convection currents, and eventually the water boils as the molecules can no longer remain in contact with each other and turn into a higher state of energy called a gas, in this case, steam. it’s Physics 101, really.
Because the amount of heat energy is ‘constant’, when it’s freezing cold in America, it’s stinking hot somewhere else, and at this time of the year, that means us in the Southern Hemisphere. That extra energy is causing more and more extreme weather, both here, and over there. As this sort of weather becomes more normal, the sum total of all the weather events become the new climate, and presto, we have Climate Change. And no Tony Abbott, it is NOT CRAP.
Cornell’s Charles H. Greene, professor of Earth and Atmospheric Sciences, and Bruce C. Monger, senior research associate in the same department, have detailed this phenomenon in a paper published in the June issue of the journal Oceanography.
Greene says, “What’s happening now is that we are changing the climate system, especially in the Arctic, and that’s increasing the odds for the negative Arctic Oscillation conditions that favour cold air invasions and severe winter weather outbreaks by diminishing latitudinal pressure gradient which is linked to a weakening of the winds associated with the polar vortex and jet stream. Since the polar vortex normally retains the cold Arctic air masses up above the Arctic Circle, its weakening allows the cold air to invade lower latitudes..”
Here is a good video explanation of what is going on:
Now what I want to know is…. what will happen to the jetstream in the Southern Hemisphere?