Artificial solution to global warming?
Nobel Prize-winning chemist Professor Paul Crutzen has outlined a drastic 'emergency route' from global warming, which could use artificial means to combat the slow rise in carbon dioxide (CO2) emissions from burning fossil fuels, and the resultant rise in global temperatures. However, Professor Crutzen remains pessimistic as to whether humankind can react anything like quickly enough to do anything about the changing climate. The chemist calls for research into the possible effects of geo-engineering, to counter the effects of global warming. This year, northern Europe has experienced one of the hottest months in history. In July, the UK recorded its hottest month since records began in 1914, with a mean temperature over day and night of almost 18°C. Many take this as evidence of global warming. Professor Crutzen, a Dutch national who works at the Max Planck Institute for Chemistry, won his Nobel Prize in 1995 for his work into the global formation and depletion of ozone. Here, he examines a less familiar but no less significant consequence of industrialisation - the increase in the Earth's albedo effect - known as 'global dimming'. The effects of both CO2 and the albedo are natural and normal. The problem is when these phenomena are exaggerated or amplified by the action of humans. Industrialisation has increased the power of both CO2 (global warming) and the albedo (global dimming). Global dimming has in many ways the opposite effect to global warming. While CO2 emissions cloak the Earth like a blanket, warming it up, particles or vapour in the air or even reflective surfaces on Earth act like a mirror, reflecting heat energy back into space. When the US grounded all flights following the 11 September 2001 attacks in New York and Washington DC, temperatures in the US actually rose. The reason is thought to be the absence of jet engine vapour trails, which would normally increase the albedo effect. 'By far the preferred way to resolve the policy makers' dilemma is to lower the emissions of the greenhouse gasses. However, so far, attempts in that direction have been grossly unsuccessful,' says Professor Crutzen, in an editorial for the journal Climate Change. He points out that current models of climate change predict a rise in temperatures this century that could outstrip the Integrated Pollution Prevention and Control projections of 1.4-5.8°C. In fact, while levels of CO2 need to drop by up to 80 per cent, CO2 levels are still rising. Professor Crutzen instead suggests that enhancing the Earth's albedo effect could be a way to reduce global warming. 'This can be achieved by burning S2 [sulphur] or H2S [hydrogen sulphide], carried into the stratosphere on balloons and by artillery guns to produce SO2 [sulphur dioxide],' he writes. He compares this approach to the eruption of Mount Pinatubo in 1991, which resulted in a reduction in global temperatures of 0.5° the following year. However, he acknowledges that 'The main issue with the albedo modification method is whether it is environmentally safe, without significant side effects.' Examining the effects of volcanic eruptions, it seems that the effects would be temporary. Professor Crutzen explores several possibilities for introducing gases or particles into the stratosphere, but believes that such measures could be set in motion at very short notice, and at relatively little cost - he estimates USD 25-50 billion. He points out that global warming is already responsible for some animal extinctions and water expansion due to temperature rise is an acknowledged threat before the effects of melting ice-caps. Increasing CO2 levels will also make the sea more acidic, threatening corals and other delicate sea-life. 'If sizable reductions in greenhouse gas emissions will not happen and temperatures rise rapidly, then climate engineering, such as presented here, is the only option available to rapidly reduce temperature rises and counteract other climatic effects,' he says. While this proposed solution may sound drastic, 'I must stress that the albedo enhancement scheme should only be developed when there are proven net advantages and in particular when rapid climate warming is developing, paradoxically, in part due to improvements in worldwide air quality. Importantly, its possibility should not be used to justify inadequate climate policies, but merely to create a possibility to combat potentially drastic climate heating,' he says. Professor Crutzen believes that the main priority is to reduce CO2 emissions, but there is 'little reason to be optimistic', he says. If reductions in CO2 prove unsuccessful, then he believes that a drastic reaction, such as the one he proposes, could be used with measures like CO2 sequestration and increased forestation. However, he calls for research first - to model how any artificially introduced sulphur compounds into the stratosphere could work, and if there would be any unexpected side-effects. Professor Crutzen believes the best solution for all would be to reduce CO2 emissions, but this, 'looks like a pious hope' he says.
Countries
Germany, Netherlands