Friday, 27 September 2013

Climate change: concerted action needed

We humans are told [wrongly] that ever growing narrowly defined wealth levels are possible and desirable on a finite planet. Human population has accelerated to over seven billion and looks set to reach ten or eleven billion people, all needing energy, food, water, shelter…and aspiring to ever growing wealth. Resource intensive technologies, especially fossil fuel dependent ones, are used for industrial scale farming, mass production, transportation and more.

Given the accelerating rate and intensity of resource use and the pumping out of huge amounts solid, liquid and gaseous wastes it would be a surprise if there was no significant impact on our climate, with billions of tonnes of the waste dumped into the air. Thus the Intergovernmental Panel on Climate Change asserted on the release of their very recent report on the scientific evidence that  they are 95% certain that humans are the "dominant cause" of global warming since the 1950s’ (BBC story here).  

Of the 4 hundred billion tonnes of carbon in the form of natural gas, oil and coal present underground before the industrial revolution it’s taken us about 250 yrs to burn 0.5 hundred billion tonnes. We are currently set to burn the next 0.5 hundred billion tonnes in just 35 years. Do we really think this is a good idea??

Carbon dioxide in the air is 39% higher than at the start of industrialisation in 1750. Methane is up 158%. Nitrous oxide is up 20%. People, especially those living in the most economically developed societies, currently impact heavily on the carbon cycle (see image below). Total carbon dioxide equivalent emissions per person per year in the UK are now more than 10 tonnes, when a sustainable level is 2 tonnes. Elsewhere in the economically developed world it can be higher than this eg in the USA.

In constructing homes, factories, roads...people consume huge quantities of fossil fuel and cement. Extracting/producing, transporting and using fossil fuels and cement in itself releases large amounts of carbon. In heating and lighting homes and using many gadgets people consume large amounts of natural gas and electricity (largely produced by burning fossil fuels in power stations).

In transporting themselves around by car and their factory mass produced and consumed goods around the globe by heavy lorry, planes and ships, huge amounts of petrol, diesel and aviation fuel are burned, emitting carbon. Demand for land is high and growing eg to feed a growing world population and to meet high demand for meat. Beef farming in particular is land and energy intensive - large scale deforestation (see image) has occurred to make land available for it.

The World Metrological Organisation says that global warming accelerated from 1971 to 2010 and the decadal rate of increase between 1991-2000 and 2001-2010 was higher than ever. The world is warming and the changing weather is causing increasing amounts of damage. The latest World Meteorological Organization analysis of climate between 2001 and 2010 stated that the decade was warmest since measurements began in 1850 for both land and ocean surface. More national temperature records were reported broken in the last decade than in any previous one.

In the last decade we’ve seen heat waves in Europe and Russia, Hurricane Katrina in the US, tropical cyclone Nargis in Myanmar, droughts in the Amazon basin, Australia and East Africa, and huge floods in Pakistan. Sea levels rose approximately twice as fast as the one hundred year trend. Arctic sea ice has rapidly declined and there is accelerating net loss of ice sheet mass in Greenland and Antarctica and from glaciers around the globe.

The current hot debate about the apparent pause in atmospheric warming centres on looking at ten to fifteen years of data (see part of the debate here). This is a short period in climate terms and becomes most useful if one looks at decadal averages and in the context of the overall trend (see above). Remember that the classical definition of climate is the range of weather phenomena averaged over 30 years. The climate system is complex, with high inherent variability so one should not expect a smooth global temperature curve (see graph above). More data is far better than less, so what counts is the long-term underlying trend. This trend is clearly in an upward direction.

One reaction to all the climate change evidence: the UK Climate Change Act, 2008 which became law under the last Labour Govt, which sets a carbon reduction target of at least 80% by 2050 from 1990 levels and carbon budgeting. However, the current Conservative/Liberal Democrat Coalition Govt has a long list of green failures. Despite its ‘greenest government ever’ claim it has: dropped the pledge to cut EU emissions by 30% by 2020 and is instead getting the EU "back on track" to cutting energy consumption by 20% by 2020; abandoned a planned rise in the renewable energy target; axed a commitment to replace air passenger duty with a per-flight tax; severely limited the scope of green financial products supposed to enable people to invest in green infrastructure; favoured greater reliance on finite and climate change causing natural gas; favoured fracking for shale gas....see here for more.

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