The recent heat wave in the Northern Hemisphere has brought a foretaste of what global warming – the ongoing long-term increase in the Earth’s average temperature, an aspect of climate change – can be like in future.
A recent study by the Union of Concerned Scientists, using 18 climate models to predict changes in heat and humidity across the contiguous USA, found that it will face a substantial rise in the number of extremely hot days. Even if something is done to reduce greenhouse gas emissions (blamed for climate change) this will occur, but if nothing is done, the impact could be far more harmful.
The heat wave engulfing Europe is heading north, which may have disastrous consequences. Unprecedented wildfires have been raging north of the Arctic Circle, so large that they are visible form space, causing climatic devastation.
“The northern part of the world is warming faster than the planet as a whole,” reported the World Meteorological Organization (WMO). “That heat is drying out forests and making them more susceptible to burn.” The resultant wildfires, it said, released a minimum of 50 megatonnes of carbon dioxide, greater than Sweden’s annual emissions.
The heat wave could also speed up the melting of the Arctic ice cap, particularly the crucial ice sheet covering 80% of Greenland – if this were to melt, it could cause a cataclysmic rise in sea levels, effecting all the world’s coastal cities. The recurrent flooding of seaside roads along the southwest coast of Sri Lanka may be a consequence of this – with dire ramifications for Sri Lanka’s tourist trade.
Climate scientists in Singapore warn that the city-state’s coastal defences should be strengthened as a measure against sea-level rise. An increase in global temperatures of 0.5°C may lead to a 10cm rise in sea level, according to a study by a team led by Professor Adam Levermann, of the Potsdam Institute for Climate Impact Research in Germany, which says that the West Antarctic ice sheet has begun a “self-sustaining ice discharge.” It says that the more than 3-metre concomitant sea level rise may cause severe problems in highly-populated coastal areas, including metropolitan cities – such as Colombo, Galle and Jaffna in Sri Lanka.
Melting of the sea ice in the Arctic can also accelerate climate change. A recent scientific paper indicates that the white surface of the Arctic ice pack is key to reflecting solar rays away from the Earth and reduce temperatures, preventing the faster heating up of the dark oceans. The shrinking of the polar ice cap, already at a record this year, may be worsened by the heat wave. Losing this ice cover would be the same as adding 1 trillion tonnes of carbon dioxide to the atmosphere.
The acceleration in the melting of the ice caps is causing scientists to study how to ameliorate the effects. Professor Levermann, of the Potsdam Institute for Climate Impact Research, told Reuters news agency that “We are already at a point of no return if we don’t do anything.” Levermann’s team of climatic researchers has come up with a radical proposal to thicken the melting ice by creating a layer of snow artificially. They suggest using over 12,000 wind-powered pumps to spray cold sea water onto the surface of the West Antarctic ice sheet, to create snow.
However, they warn that carrying out their proposal practically “would mean an unprecedented effort for humankind in one of the harshest environments of the planet.”
This is just one of the less extreme schemes for offsetting the effects of climate change, which underline the growing anxiety among scientists. Harvard University professors David Keith and Frank Keutsch hope to launch a small-scale atmospheric experiment to test the feasibility of geo-engineering, i.e. altering the climate deliberately. This would be the first such experiment outside the laboratory.
They expect to launch a balloon, equipped with propellers and sensors, to high altitude. There, it would spray a fine mist of sulphur dioxide, alumina or calcium carbonate into the upper atmosphere. The sensors aboard it would then measure how much the mist particles reflect, how they scatter or combine and how they react with atmospheric compounds. This could lead towards scattering particulate matter on a large scale, in critical areas of the atmosphere, to reflect the sun’s rays before they can heat up the lower atmosphere.
However, one section of the scientific community is apprehensive that such experiments can legitimise the idea that there can be a “technological fix” for the effects of global climate change and prevent meaningful action being taken to prevent it, or at least slow it down. There are also fears that these experiments could lead to other, unforeseen problems, or to their use as weapons for intimidating smaller nations.