Global Warming - Rising temperatures, rising concern
Although there are those who maintain that the phenomenon either does not exist or else is not as serious as is being claimed, the majority view - certainly within the scientific community - is that global warming is not only very real, but that it represents the most significant environmental issue of our time. An issue that, if not addressed properly and promptly, could have a profound effect on the future of the Earth and its inhabitants.
While the detailed science is complex and contentious, the basic premise of global warming is relatively simple. The earth's atmosphere contains a delicate balance of so-called "greenhouses gases." These gases, which include water vapour, carbon dioxide, methane, ozone and nitrogen oxides, serve to regulate the earth's temperature by allowing sunlight through to heat the earth's surface and then trapping and absorbing some of that heat as it is reflected back into space as infra-red radiation - the so-called 'greenhouse effect.'
All greenhouse gases exist naturally, and are essential to the earth's survival - without them the global temperature would, it has been estimated, be some 33 Celsius colder than it actually is.
According to the UN's Intergovernmental Panel on Climate Change (IPCC), however, an international body comprising over 2,500 scientists, human activity - in particular the burning of fossil fuels by power stations and motor vehicles - has significantly increased the levels of some of these gases.
The atmospheric concentration of carbon dioxide, for example, the main by-product of fossil fuel combustion, has risen by some 31 percent since the start of the Industrial Revolution in 1750, and is now at its highest level - 378 parts per million according to the US government's Climate Monitoring and Diagnostics Laboratory - for over 400,000 years. Widespread deforestation has exacerbated the situation by removing the plants and trees that would naturally absorb and reprocess some of this excess carbon dioxide.
The result has been that the natural balance of the world's greenhouse gases has been upset, leading to a "thickening" of the earth's atmosphere. That in turn has led to more and more of the sun's heat being retained within the atmosphere and an attendant rise in the earth's surface temperature (the last decade has witnessed the three hottest years since records began in the mid-19th Century).
IPCC statistics reveal that overall the world's temperature has risen by 1 degree Fahrenheit (0.6 degrees Celsius) over the past century, and is projected to increase by a further 3 to 10 degrees Fahrenheit (1.6 to 5.5 degrees Celsius) by 2100.
Although the figures might not in themselves appear especially dramatic, and certainly do not represent the first time in its history the earth has experienced significant temperature shifts, the speed at which the current warming is taking place, the fact that it appears to have been precipitated by our modern way of living and, most important, the way it is impacting on the earth's climate patterns, is causing huge concern not simply to scientists and environmentalists, but to politicians as well.
Increased incidence of droughts, floods, forest fires, storms, heat waves, water shortages, extreme weather events - all, it is argued, are directly or indirectly attributable to global warming, and all are likely to become more severe as the mercury levels continue to rise.
As IPCC chairman Dr. Rajendra Pachauri put it recently: "Climate change is for real. We have just a small window of opportunity and it is closing rather rapidly.
"There is not a moment to lose. We are risking the ability of the human race to survive."
Gradual consensus
The scientific consensus on global warming and climate change has taken well over a century to come together.
It was the 19th Century French mathematician and physicist Jean-Baptiste-Joseph Fourier (1768-1830) who first came up with the idea for what would subsequently be labelled 'the greenhouse effect.'
In an 1824 article entitled "General Remarks on the Temperature of the Terrestrial Globe and Planetary Spaces" Fourier likened the earth's atmosphere to a giant bell-jar, suggesting that gases within that atmosphere helped trap some of the sun's heat as it reflected back off the earth's surface, thereby sustaining life on the planet.
While Fourier laid the theoretical foundations, it would be another seventy years before a definite connection was made between human activity, increased greenhouse gas concentrations and rising global temperatures.
The man responsible was Nobel-prize winning Swedish scientist Svante Arrhenius (1859-1927), whose research subsequently earned him the title 'The father of global warming' (the phrase 'global warming' was not itself coined until the 1970s).
In an 1896 paper Arrhenius argued that increased atmospheric carbon dioxide concentrations from the burning of fossil fuels would serve to increase the amount of heat being retained in the earth's atmosphere, thereby raising global temperatures (he estimated that a doubling of the CO2 concentration would lead to a 5-6 degree Celsius temperature rise).
Arrhenius' calculations formed the basis for all future work on global warming, notably that of pioneering climate scientists such as Britain's Guy Callendar, who in the 1940s compiled measurements demonstrating that the earth's temperature had already been rising for well over a century; and Charles Keeling of the US, the first scientist to systematically measure atmospheric carbon dioxide levels at the Mauna Loa observatory in Hawaii.
Thanks to this work a gradual picture has been pieced together of a world that is steadily and inexorably growing hotter as a result of mankind's lifestyle habits. And as that picture has become clearer so the calls for action have become louder and more widespread.
Tackling the problem
In 1985 the United Nations Environment Programme (UNEP), the World Meteorological Organization (WMO) and the International Council of Scientific Unions (ICSU) sponsored a groundbreaking conference at Villach in Austria, at which for the first time the scientific community forged an official consensus on the issue of global warming, acknowledging that it was definitely taking place, that its causes were largely man-made, that it was affecting the world's climate and that an urgent international response was required to try to tackle the situation.
Three years later, in 1988, the IPCC was established, bringing together expert scientists from around the globe to "assess the scientific, technical and socio-economic information relevant for the understanding of climate change, its potential impacts and options for adaptation and mitigation."
Four years after that, in 1992, at the milestone United Nations Conference on Environment and Development - better known as the Rio Earth Summit - the United Nations Framework Convention on Climate Change (UNFCCC) was signed by the governments of 154 nations, its stated objective being "to achieve stabilization of greenhouse gas concentrations in the atmosphere at a low enough level to prevent dangerous anthropogenic interference with the climate system."
While the UNFCCC itself contained no mandatory limits on greenhouse gas emissions by signatory nations, it included a provision for subsequent amendments or "protocols" that would set such limits.
The best known of these protocols was negotiated at Kyoto, Japan, in 1997, and committed the world's leading industrialised nations to reducing their collective emissions of the six most harmful greenhouse gases by 5.2 percent compared to 1990 levels by the year 2012.
While the Kyoto Protocol remains flawed - both Australia and the U.S., the latter responsible for 25 percent of the world's carbon dioxide emissions, have refused to ratify it - it is generally acknowledged as the most significant international attempt to date to get to grips with the global warming phenomenon.
It is likewise acknowledged, however, that far more needs to be done if there is to be any hope of bringing that phenomenon under control.
As Klaus Toepfer, the director of the UN Environment Programme admitted recently: "Kyoto is only the first step in a long journey."
Dissenting voices
There remain those who, despite the large - and growing - body of evidence to suggest that human activity is causing global warming, and that global warming is in turn causing substantial and potentially disastrous changes to the Earth's climate systems, that the situation is not as serious as scientists are making out.
"Although there is a very broad consensus that global warming is happening and is a problem," says Dr. Heike Langenberg, Physical Science Editor for Nature Magazine, "There are a very few people in the other camp, and they tend to be very vocal."
The best known of these is Danish academic Bjorn Lomborg, who in his 2001 book the Skeptical Environmentalist argued that while global warming is irrefutably occurring, its effects are not necessarily as catastrophic as has been suggested, and that even if they were there is very little that we can do about it.
"Even if everyone (including the United States) did Kyoto and stuck to it throughout the century," he wrote in a 2004 article, "the change would be almost immeasurable."
Rather than waste money on quixotic attempts to reduce greenhouse gas emissions, he suggests, we should instead address more pressing humanitarian issues such as disease, education and access to clean drinking water.
"We need to stop our obsession with global warming, and start dealing with the many more pressing issues in the world, where we can do most good first and quickest."
Others, principally in the U.S., have gone even further than Lomborg, suggesting that global warming does not actually exist.
"What we have," says Bonner Cohen of the Washington-based conservative think-tank The National Centre for Public Policy Research, "is a theory that the burning of fossil fuels is contributing to a potentially dangerous warming of the planet - a theory whose validity has yet to be determined.
"Right now it is nothing but a hypothetical problem. What you have is a large number of people who have a vested interest in keeping the global warming issue alive. Their livelihoods depend on it."
Irreversible Damage
Despite such nay-sayers, however, the overwhelming opinion within the scientific, and increasingly the political community is that global warming is a very significant problem.
Not only that but that the phenomenon and its effects are becoming steadily more severe, and that we are fast approaching a tipping-point beyond which even concerted international action will not be able to recover the situation.
Recent studies, for instance, have revealed that rising global temperatures have caused a huge expanse of frozen peat bog in Western Siberia to start thawing for the first time in 11,000 years. If the thaw continues at current rates, billions of tonnes of methane - a far more potent greenhouse gas than carbon dioxide - will be released into the atmosphere, significantly accelerating the global warming snowball.
"The situation is an ecological landslide that is probably irreversible and is undoubtedly connected to climactic warming," says Dr. Sergei Kirpotin of Tomsk State University, who first recorded the thaw.
Even the Bush administration, which has to date remained resolutely sceptical about global warming, has started to acknowledge the potential seriousness of the situation.
In a statement at the recent G8 summit in Scotland the U.S. president admitted that "the surface of the Earth is warmer and that an increase in greenhouse gases is contributing to the problem."
Acknowledgement of the problem is one thing, however, solving it another. Given that the burning of fossil fuels remains fundamental to the economies not simply of industrialized nations, but many developing ones as well, there is widespread pessimism about whether those nations can make sufficiently large cuts in their greenhouse gas emissions sufficiently quickly to slow and halt the global warming conveyor. As Dr. Greg Marland, a climate expert with the U.S. Carbon Dioxide Information Analysis Centre, puts it: "I have a mantra - Fix, change, tinker or cope. Fix the current energy system, change the current energy system, tinker with the climate system, or cope with the changes that come about as a result of global warming.
"My feeling is that we're going to end up doing a lot of coping."
External Links
Intergovernmental Panel on Climate Change - http://www.ipcc.ch/Climate Monitoring and Diagnostics Laboratory - http://www.cmdl.noaa.gov/
Mauna Loa Observatory - http://www.mlo.noaa.gov/default.htm
United Nations Environment Programme - http://www.unep.org/
World Meteorological Organization - http://www.wmo.ch
International Council of Scientific Unions - http://www.icsu.org
Nature Magazine - http://www.nature.com
Bjorn Lomborg - http://www.lomborg.com/
Carbon Dioxide Information Analysis Centre - http://cdiac.esd.ornl.gov/
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