| Kyoto: a Cure for Climate Change? |
| Tuesday, 11 January 2005 | |
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The Earth's climate is changing, causing dramatic alterations to the natural landscape. With potentially catastrophic events predicted by the UN's Intergovernmental Panel on Climate Change (IPCC) that may affect billions of people, governments from around the world have become actively involved in attempts to remedy the problem. Preparing to spend billions of pounds, many have signed up to the Kyoto Protocol, which becomes legally binding on 16 February 2005. The scale of the issue
Although a 0.6ºC rise in temperature may not sound significant, in 2004 the Arctic Climate Impact Assessment (ACIA) stated that this has already been enough to melt glaciers and icecaps, and to cause a decrease in summer Arctic sea ice by 20% over the past 30 years. This in turn has warmed and acidified oceans, caused a rise in sea levels and produced extreme weather phenomena across the globe, including hurricanes, heat waves and prolonged droughts. These changes are all consistent with a warming climate near the Earth's surface. Furthermore, according to scientists at the National Institute of Health and Medical Research, there were nearly 15,000 additional deaths during August 2003 in France alone, as a direct result of the soaring temperatures that summer. A 1.4ºC increase in temperature would result in even greater catastrophes. The IPCC predicts increasingly violent storms, droughts and flooding and disruption of water supplies. Most of those who would suffer are in poorer countries, particularly Latin America, Africa and Asia, as it is these countries that will bear the brunt of the climate changes. After reviewing the available scientific data, the IPCC concluded that, "there is new and stronger evidence that most of the observed warming observed over the last 50 years is attributable to human activities", especially the increase of greenhouse gases in the atmosphere. These findings have been confirmed by other committees of experts, such as the United States National Assessment Synthesis team set up by the US Congress. While human activity has increased the concentration of all greenhouse gases, of particular concern is that atmospheric concentrations of carbon dioxide are rising faster than at any time in Earth's history. Although it is accepted that carbon dioxide levels naturally fluctuate, current levels have been increasing over 200 times faster than the background rate, a fact clearly demonstrated by ice core studies like the Law Dome Ice Core project. This increase is mainly the result of burning fossil fuels, such as coal, oil and natural gas, which release carbon dioxide into the atmosphere. These energy sources are used for almost everything we do - from powering our cars and heating our homes, to fuelling the power stations on which we rely for everyday life. Carbon dioxide, methane, nitrous oxide and water vapour all occur naturally in the atmosphere, and all play an important role in keeping the Earth some 33ºC warmer than it would be otherwise by acting as a layer of insulation, trapping some of the heat reflected off the Earth. However, humans have dramatically altered the natural balance of greenhouse gases through increasing atmospheric concentrations of carbon dioxide, methane and nitrous oxide. Indeed, according to data from NASA, humans release over 6.5 billion tonnes of carbon dioxide a year into the atmosphere. The increase in concentration of greenhouse gases leads to greater insulation around the Earth, resulting in the rise in temperature. The atmosphere allows solar energy through, but as it is reflected off the Earth, the wavelength of the radiation alters so it cannot pass back out through the atmosphere into space. Instead, it remains trapped causing an increase in temperature. In an attempt to combat climate change, many countries, including the UK, are preparing to invest substantial resources to reduce the levels of greenhouse gases that are emitted, particularly carbon dioxide. The Kyoto Protocol is the result of a meeting of over 160 nations, who agreed in 1997 that industrialised countries would reduce their collective emissions of greenhouse gases by 5.2% compared to the year 1990. However, although signed in 1997, the Kyoto Protocol will only become legally binding on 16 February 2005,with those that have ratified the Protocol having until 2012 to achieve this reduction. In the UK, the government is attempting to achieve its targets by, for
example, using less coal for electricity generation, and replacing this
method with renewable energy sources such as wind power. Is Kyoto the cure? Some countries, including the US, have refused to ratify the Kyoto Protocol. This lack of commitment demonstrates that the implementation of global policy to combat climate change has not been without international dispute, amongst both scientists and politicians. In the past, this controversy was partly centred on the question of whether human activity was responsible for climate change, or whether it was the result of variation in solar radiation. Those who believed that human activity was to blame thought that if man-made emissions were cut, then the effects of climate change could be radically reduced. This is one of the key ideas behind the Kyoto Protocol. Of course, climate change is not just caused by humans. Since the Earth's climate system is driven by the sun, it is affected by solar variability. Another important factor affecting the climate is volcanic eruptions, which can inject large amounts of dust into the atmosphere. The IPCC have more recently concluded that the change in climate is the result of both human and natural activity. Their 2001 results illustrate that anthropogenic influences, such as greenhouse gases and sulphate aerosols, provide a plausible explanation for a substantial part of the temperature changes over the past century. They find that the best agreement between model simulations and observations is obtained when both anthropogenic influences and natural influences, such as solar variation and volcanic activity, are combined. The IPCC also cautions that although the influences included in their study are sufficient to explain the observed changes, this does not exclude the possibility that other influences may have also contributed. The climate changes on many different timescales, some of them millions of years long. It is well-known that there are processes that affect climate change over such times, and this is the subject of paleoclimatology. For instance, the Earth's position and orientation relative to the sun are not fixed, but vary in what are known as Milankovitch cycles. Milankovitch cycles play an important role in explaining ice ages and other climate variability over thousands of years. However, for the prediction of climate change in the 21st century, long-term effects like the Milankovitch cycles are thought to be much less important than the aforementioned anthropogenic and natural influences. The climate is a very complex system, and the warming of the globe may
affect it in unexpected ways. A particular worry is that global warming
may disrupt the global circulation system, known as the ‘Ocean
Conveyor'. This can contribute significantly to the warming and cooling
of the Earth. The Ocean Conveyor transports vast amounts of heat around
the planet via the Gulf Stream, warming the North Atlantic region by as
much as 9ºC, and resulting in milder winters and warmer summers. For
the Ocean Conveyor to function, there must be a critical concentration
of salt water, but as the Earth warms up and glaciers and ice caps
melt, increasing amounts of fresh water are released into the oceans,
diluting the salt water. As a result, the Conveyor shuts down, causing
substantial cooling throughout the North Atlantic region. Records from
a variety of sources show that this shutdown has happened several times
before, and appears to be happening again. Data collected in 2002 found
that the North Atlantic had been diluted dramatically by fresh water,
with evidence of a slow-down of the Ocean Conveyor reported in 2001.
However, it is difficult to make an actual prediction as to when the
Ocean Conveyor will shut down, as the exact critical concentration of
salt water on which it depends is not yet known. So in the longer term,
the Northern Hemisphere at least may be heading towards a cooling
climate, rather than a warmer one.
So, what now? Most national governments are committed to the Kyoto Protocol, and to reducing the emission of man-made greenhouse gases. But is the Kyoto protocol good enough? A model by Tom Wigley, one of the authors of the IPCC reports, shows that an expected temperature increase of 2.1ºC by 2100 would be diminished by the Kyoto Protocol to an increase of 1.9ºC.This latter temperature is the predicted increase for 2094 without emission reduction. Therefore, the temperature increase that the planet would have experienced in 2094 would simply be postponed by six years. The statistician Bjørn Lomborg has estimated that the implementation of the Kyoto Protocol may cost up to one trillion US dollars worldwide. He believes that the cost in the US alone would be greater than that of providing global access to clean drinking water and sanitation - a measure that could prevent two million deaths a year and protect half a billion people from serious illnesses like cholera. This raises many questions, perhaps most significantly that if the Kyoto Protocol will not stop climate change, but merely delay it, would the money needed to implement it be more beneficially spent on providing global access to clean water, and maybe preparing for the inevitable? Conclusion It is clear that the Earth is getting warmer, with potentially
devastating consequences for billions of people, especially those in
developing countries and those who live in low-lying areas. Human
activity has been shown to cause an increase in the amount of
greenhouse gases in the atmosphere, most notably carbon dioxide, and
there is robust scientific evidence that demonstrates that the change
in global temperature is connected to both human influences, like the
increase in greenhouse gases, and natural influences, such as solar
variability. So, what are we to do? Should developed nations try to do
something about climate change? Should there be a stricter Kyoto-style
protocol? Or should we just accept that climate change is inevitable,
and work on alleviating its adverse effects? If there is a balance,
what is it? If you had to spend the money, what would you do? Carolyn Dewey is a medical student based at Addenbrooke's Hospital. Additional research and writing by Björn Haßler
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During the last 100 years, the Earth's temperature has risen by a
global average of 0.6ºC. The IPCC predicts that it will continue to
rise by between 1.4ºC and 5.8ºC over the next century. This means that
the Earth is already warming faster than at any other time in the last
thousand years, with the 1990s the warmest decade since records began.
Even if the Earth does warm up by only a further 1.4ºC, this increase
would mark the most rapid change in 10 millennia. News Archives
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