Global Warming Edges Closer to Home

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What a difference a decade makes. Ten years ago people talked about global warming as something that would affect the developed world decades ahead, if not centuries. Even the phrase ‘global warming’ was actually quite comforting. Sea level rise impacting low-lying countries (i.e. ‘not here’) towards the end of the century (i.e. ‘not in our lifetimes’) was the prediction that got most media coverage. Somehow it was a problem that people felt would either not impact them, or would solve itself given time. Worst case, we’d have to find some place other than the Maldives for our more exotic holidays.

But earlier this month, the US Government released its latest National Climate Assessment, documenting numerous changes to the climate of the United States that are already happening in every region of the country and affecting several key industries.

It’s an impressive document and so it should be – more than three hundred scientists and sixty Federal advisors have labored on it for four years. It weighs in at over 800 pages and documents numerous recent changes to the American climate – including more frequent heavy precipitation events in the north-east, increased levels of drought, water stress and wildfires in the south-west, and more marine acidification in the Pacific north-west.

Having said that, it’s not all doom and gloom. Surprisingly positive progress has been made in the underlying problem of reducing CO2 emissions in the US – in fact, between 2008 and 2012, carbon dioxide emissions were reduced by almost ten per cent, mostly by moving more electricity production from coal-fired to gas-fired power stations. In some places a warmer climate has actually resulted in higher crop yields, thanks to the longer growing season.

But the good news is definitely outweighed by the negative impacts, and what is most noticeable is that many of these impacts are no longer mild inconveniences; they are starting to affect people’s lives quite directly as well as the economy. Increased acidification has already impacted shellfish hatcheries and caused some to close down. Corn producers in Iowa, oyster growers in Washington State, and maple syrup producers in Vermont have all experienced climate-related changes outside of the normal bounds. And of course, more frequent extreme weather is something that’s been particularly noticeable to all of us the past few years – longer and hotter summers, more severe rainstorms and hurricanes, less sea-ice off Alaska leading to greater coastal erosion.

What is also quite striking is the tone of the report: it speaks less about reversing global warming and much more about mitigating the effects – and above all about adaptation to the inevitable. At long last it reads like an admission that if you’re hurtling towards a concrete wall in your Ferrari, then merely taking your foot off the gas won’t avoid a calamity, only that it might make the impact marginally more survivable.

Highlighting this inevitability, the report specifically admits that ‘because of past emissions … some additional climate change and related impacts are now unavoidable’. Even under an optimistic scenario of an immediate ‘significant reduction’ in greenhouse gas emissions their estimate is that global temperatures will continue to increase another 1.9˚F (1.1 C) by the end of the century, thereby doubling the change witnessed already.

What ‘adaptation’ might mean in reality is harder to pin down. They suggest building more bike lanes, planting the roofs of buildings with grass to absorb CO2, building houses near the coast on stilts to allow storm surges to pass underneath, and even updating city building codes to better protect against insects carrying dengue fever (higher temperatures will inevitably mean more diseases).

State adaptation plans are not much better: in Florida, they passed a law limiting usage of water for their lawns, and in Montana they will set up a climate change website. Only Maine seems to have a pragmatic approach – they will require future coastal buildings to be set back from the future shoreline position, based on a projected two foot rise in sea level.

The authors say that they hope their report will provide ammunition for President Obama and Congress to take action. There is certainly room for that. One of the most revealing maps in the entire report is a colour-coded map of the US showing status of climate adaptation plans by state. Apart from the coastal states, the entire map is blank.

David Millar is a science writer with an interest in climate change past and present.

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