Up to a thousand people have died following torrential rain and landslides in Rio de Janeiro. An area around the size of Western Europe was drowned for more than a fortnight in Brisbane. And prior to this, the heaviest single recorded snowfall event fell upon Sydney.
Match this to the historic levels of snow throughout Europe and North America, where last month every mainland state except Florida experienced a blanket of the white stuff and you have to start wondering what on earth is going on with…Earth. Where is the equilibrium that we have been told time and again ensures that the fabled Gaia – the earth’s various systems and energy balances – remains a constant throughout the planet?
The science behind climate change has been extensively reported over the past few years, with conferences in Copenhagen and Cancun aiming to reach international agreement on what should be done to cope with or offset climate change.
Things that are definitely happening
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Causes of what is happening
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The inputs that could still make a difference; what do we still not know?
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But this latest batch of extreme weather has its origins in oscillations of the oceanic and atmospheric systems in the southern hemisphere can be attributed as the triggers for much of the peculiar precipitation. Greenhouse gases in the atmosphere are not the main culprit here.
Notably, this includes El Niño – well documented during warming periods - and La Niña - the stubborn little sister that cools Equatorial waters.
Fish stocks off South America dwindle in El Niño conditions, with the warmer waters preventing many of the shoals of anchovies and their predators from coming close to the coast, which reduces the fishing industries’ economic success.
But La Niña is not unaccountable for mood swings, so to speak, and despite being the less familiar of the siblings up here in the northern hemisphere, its impacts across the globe are well known. And the recent snowfall across the northern hemisphere came following La Niña conditions, as well as droughts in China that have lasted around ten months.
Volcanoes in Iceland and the Philippines probably have not affected the weather patterns in this instance. Though they were both significant, the Mount Merapi eruption was not large enough and would not have led to the extreme monsoons in Australia, around 2000km from the eruption, let alone those in Brazil around 6500km away. La Niña is also likely accountable for the devastating floods in Pakistan in the summer of 2010.
Understanding what might happen to the weather over the coming months can be heavily determined by modelling what has happened so far against other La Niña events. It would be great to say for certain that it will be an Indian summer here in Britain, that crops across the world will receive their recommended dose of water and that famine and disease won’t spread.
But if it does, remember: don’t blame it on the weatherman!
Pictures courtesy of NASA via Wikimedia Commons (snow-covered Britain) and transferred from en.wikipedia; author PMBO (Brisbane wheel).
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