Last updateSat, 22 Jul 2017 6am

You are here: Home | Agenda | Climate change | Hotting up: The science and politics of climate change

Hotting up: The science and politics of climate change

By Aditi Sen

The world is hotting up. Climate systems are changing. The 1990s were the hottest decade ever, sea levels rose by 10-20 cm during the 20th century, and atmospheric carbon dioxide levels are 31% higher than in 1750. There's overwhelming scientific evidence to prove that climate change is human-induced and closely connected to energy use and the burning of fossil fuels

It rained all day. It rained like it had never rained before. Trains stopped, cars were submerged, several died, and hundreds and thousands of people waded through the streets of Mumbai. The city that never stands still came to a grinding halt. It almost sounds like a scene from a sci-fi film, but in fact it is scarily real. Mumbai witnessed the heaviest rains ever recorded in India in July 2005. Such catastrophic weather phenomena are often seen as acts of God, and they might well be, but the increasing occurrence of extreme weather conditions in India and around the world points towards a dangerous threat -- climate change.

Though floods, drought, storms and other extreme weather conditions have always been a reality, they have been rare occurrences interrupting long periods of calm -- sudden outbursts marring nature's largely gentle rhythm. Now, because of human-induced climate change, that gentle rhythm is breaking up. Overwhelming scientific evidence indicates that climate change is real -- the world is warming up and climate systems are changing.

The science of climate change

Earlier this year, in February 2006, scientists found that the vast ice sheets over Greenland are melting far faster than previously believed, with twice as much ice going into the sea as was going in five years ago. What happens in the remote Arctic may seem far removed from what happens in the tropics of India, but the implications for climate change could be dramatic. If the Greenland ice sheet melted completely, it would raise global sea levels by about 7 m. The oceans play a pivotal role in the climate system. Changes in ocean circulation or water properties can disrupt this hydrological cycle on a global scale, causing flooding and long-term drought in various regions. The El Nio phenomenon is but a hint of how oceanic changes can dramatically affect where and how much precipitation falls throughout the planet.

Findings from the Intergovernmental Panel on Climate Change (IPCC), which has been established by the World Meteorological Organisation (WMO) and the United Nations Environment Programme (UNEP), show that the global average surface temperature increased by 0.6C over the course of the 20th century. Scientists have recorded the 1990s as the hottest decade in the world since the industrial revolution began. As a result of global warming, the extent of snow has decreased by about 10% since the 1960s, while mountain glaciers have retreated rapidly. The global average sea level rose by 10 to 20 cm during the 20th century, and the amount of heat stored in the ocean has measurably increased since observations began in the 1950s. .

Rainfall patterns have also changed in the northern hemisphere, with generally more rain at high latitudes and near the equator and less in the sub-tropics. Warm El Nio (which causes drought and flooding) episodes have been more frequent, persistent and intense since the mid-1970s than during the previous 100 years.    

One of the most important features of the IPCC Third Assessment Report is that it strengthens the conclusion that human activity is driving the observed climate change. The atmospheric concentration of CO2 is now 31% higher than it was in 1750, the highest it has been for the past 20 million years -- and it's accelerating. About three-quarters of the increase is from burning fossil fuels, while the rest is mostly due to deforestation. Atmospheric methane has increased even more dramatically, by 151% since 1750. Nitrous oxide and synthetic greenhouse gases (halocarbons) also continue to rise.

Much of this discussion sounds like technical babble to people. While it may seem like something esoteric that only scientists in white coats need to contend with, its impact on ecosystems, economies and local weather is real. Throughout the 10,000-year history of human civilisation, weather patterns have remained relatively constant, but the frequency of extreme weather events has increased steadily over the 20th century. The number of weather-related disasters during the 1990s was four times that of the 1950s, and cost 14 times as much in economic losses. These trends confirm the predictions of computer models: as the atmosphere warms, the climate will not only become hotter but much more unstable. Extreme events are likely to increase, and drought and floods will become more common in a number of regions. Many alpine glaciers will disappear, snow cover and the extent of sea ice will continue to wither, and sea levels are projected to rise.

Climate change also raises other important concerns: How will our health be affected by global warming; how will agricultural practices change; how will wildlife cope?

The impact of climate change

Climate change is an issue that threatens the entire globe. However, it disproportionately affects developing countries and it will be most disruptive to the poorest of the poor -- those who have the least resources and the least capacity to cope. Already there are signs that Africa's favourite crop, maize, is struggling to cope with the vagaries of a changing climate. It might even have to be dropped in favour of more traditional crops like sorghum and cassava. So says the first continent-wide study of how crop yields change with major oscillations in global climate such as El Nio and the North Atlantic Oscillation. It concludes that 20 million Africans will go hungry in the years ahead when the climate is not in their favour (Proceedings of the National Academy of Sciences, Vol 103, p 3,049).

With its huge and growing population, a long, densely populated and low-lying coastline, and an economy that is closely tied to its natural resource base, climate change could have potentially devastating impacts on India. The average temperature is predicted to rise by 2 to 4C with a doubling in CO2 concentrations. With climate change, rainfall patterns are also set to change. Western and central areas could have up to 15 more dry days each year, while, in contrast, the north and northeast are predicted to have five to 10 more days of rain annually. In other words, dry areas will get drier and wet areas wetter. In an almost sadistic twist of events, climate change will make India more susceptible to both drought and flooding. IPCC findings indicate that there will be an increase in the frequency of heavy rainfall events in South and Southeast Asia. Studies have also shown that the impact of snow melting in the high Himalayas will lead to flood disasters in Himalayan catchments.

The most dramatic effects of climate change will manifest in agriculture and forestry. These changes could in turn have profound implications for livelihoods and food security. Agriculture and allied activities continue to be fundamentally dependent on the weather in India. IPCC and other studies suggest that there will be a decrease in yields, though the percentage of decrease varies across different scenarios. Higher temperatures reduce the total duration of a crop cycle by inducing early flowering, and the shorter the crop cycle, the lower the yield per unit area.

Climate change is also likely to have a substantial impact on forestry. Climate is an important determinant of the geographical distribution, composition and productivity of forests. Therefore, changes in climate could alter the configuration and productivity of forest ecosystems. In a case study of Kerala (Achanta A and Kanetkar R, 1996), results indicate that under climate change scenarios, soil moisture is likely to decline and in turn reduce teak productivity from 5.40 m3/ha to 5.07 m3/ha. The study also shows that the productivity of moist deciduous forests could decline from 1.8 m3/ha to 1.5 m3/ha. Changes in forestry could potentially result in the extinction of some species and loss of biodiversity.

The impact on water resources is also expected to be severe. India is considered rich in terms of annual rainfall but these resources are unevenly distributed, causing spatial and temporal shortages across regions. Climate change and variability are likely to worsen the problem of water scarcity that many parts of India face. Under a changed climatic regime, the combined effects of lower rainfall and more evaporation would have dire consequences. Both these would lead to less runoff, substantially changing the availability of freshwater in the watersheds. Also, potential changes in temperature and precipitation might have a dramatic impact on soil moisture and aridity levels of hydrological zones. With changes in flows, annual runoff and groundwater recharge, water available for use will further decrease. Most major river basins across the country are likely to become considerably drier. One assessment (Hadley Centre Model Simulations) indicates that by the year 2050, the average annual runoff in the river Brahmaputra will decline by 14%.

Sea level rise associated with climate change threatens India's low-lying and densely populated coastline that extends about 7,500 km. The UNEP identifies India as among the 27 countries that are most vulnerable to sea level rise. Most of the coastal regions are agriculturally fertile, with paddy fields that are highly vulnerable to inundation and salinisation. Coastal infrastructure, tourist activities, and onshore oil exploration are also at risk. The impact of any increase in the frequency and intensity of extreme events, such as storm surges, could be disproportionately large, not just in heavily developed coastal areas, but also in low-income rural areas. A case study of Orissa and West Bengal (IPCC, 1992) estimates that in the absence of protection, a one-metre rise in sea level would inundate 1,700 km of predominantly prime agricultural land. The economic implications of such a rise could be huge -- ranging from Rs 2,287 billion in the case of Mumbai, to Rs 3.6 billion in the case of Balasore (TERI, 1996).

Climate change has other impacts that may seem less obvious at first, but would have very serious socio-economic consequences. For instance, some reports predict that India will be more prone to malaria, as changing weather patterns result in potential breeding grounds for malarial mosquitoes at higher altitudes. Adverse weather patterns will also affect large-scale infrastructure projects that are designed to have a long lifespan. The recently constructed Konkan railway, a major infrastructure project laid through the high rainfall mountain region in mid-western India, is a typical example of a high-value long-life asset exposed to climatic extremes.

The politics of climate change

The science of climate change is not a hundred percent accurate, and different models and simulations suggest different scenarios. But there are certain facts that all scientists are unanimous about -- that the earth is getting warmer, that climate systems are changing and that we are already contending with the impacts of climate change. What is also clear is that human activity has been responsible for this. But, despite such unanimous and compelling evidence on global warming the response to this threat has been sluggish and mired in controversy.

Climate change negotiations started more than two decades ago. In 1992, a global Framework Convention on Climate Change was signed under the auspices of the United Nations (UNFCC). The framework recognised that industrialised nations needed to take the first step in reducing emissions because not only were they more responsible for the problem, they also had greater capacity and resources to take corrective action since they had already reached a high level of economic development. The Kyoto Protocol was drawn up in 1997 to implement the UNFCC. According to the protocol, industrialised nations that sign the treaty are legally bound to reduce worldwide emissions of six greenhouse gases (collectively) by an average of 5.2% below their 1990 levels, by 2008-2012.

However, it took seven years for the protocol to finally become international law. For it to come fully into force, the pact had to be ratified by countries accounting for at least 55% of 1990 carbon dioxide emissions. With countries like the US and Australia unwilling to come on board, the key to ratification came when Russia, which accounted for 17% of 1990 emissions, signed the agreement on November 5, 2004. But Kyoto still lacks teeth because the United States, which is the world’s largest emitter of greenhouse gases, continues to hold out.

So where does that leave us? Emissions in America continue to rise and are now 11% higher than they were in 1990. Most countries that have signed up to Kyoto also admit that meeting their Kyoto targets will be difficult; nations are already falling behind. Spain and Portugal in the EU were 40.5% above 1990 levels in 2002. Canada, one of the first countries to sign up, has increased emissions by 20% since 1990 and has no clear plan to reach its target. Japan is also uncertain about how it will reach its 6% target by 2012.

One of the things that people are excited about as a possible solution and a potential win-win situation for both developed and developing countries is the Clean Development Mechanism. The Kyoto Protocol included provisions for two so-called “flexible mechanisms”: Joint Implementation (JI) and the Clean Development Mechanism (CDM). The CDM is supposed to be a market-based way to combat climate change. Through it, developed countries may invest in bankable projects in developing countries by paying the extra cost of upgrading to cleaner technology. In turn, they get credits for the amount of emissions reduced.

The CDM clearly has some immediate and apparent benefits -- it brings in cleaner technologies and provides financing to projects in developing countries. But on closer inspection, the deal is not as attractive as it seems. The system, as currently proposed, risks being no more than a way for wealthy countries to buy their way out of their obligations, without significantly reducing domestic emissions. These markets do not create the right conditions for the structural change needed to tackle global warming. On the contrary, they shore up the fossil fuel status quo while blocking constructive alternatives. Some developing nations, most notably India, have argued moreover that North-South trading mechanisms are inherently unfair. The way it is currently designed, the emissions-trading regime is based on an inequitable distribution of atmospheric property rights -- in other words, the right to emit carbon dioxide is not the same for all individuals on this planet. The industrial nations, for instance, decided on 1990 emissions as a baseline for allocating emissions rights to ensure continuity of their economies.

Despite the criticisms against CDM in terms of its operational inefficiencies and the ideological battle surrounding it, the 2006 Montreal climate conference which was touted as the “son of Kyoto” enshrines market mechanisms and emissions trading as the key policy response to climate change.

While neither the Montreal conference of 2006 nor the G8 summit of 2005 provided any breakthroughs, they represent a small step forward in building a consensus around the issue. It sets the stage for a dialogue on long-term climate change management beyond 2012, which is the last year of the Kyoto Protocol. On the last day of the Montreal conference, Kyoto Protocol signatories agreed to extend the treaty on emissions reductions beyond its 2012 deadline. Formal talks can now begin over the precise targets that will be set when the first phase of the Kyoto agreement expires in 2012. Montreal also sets the scene for discussing how large developing countries like India and China can be brought into the system of limiting greenhouse gas emissions.

Moving beyond deal-making and bargaining, some pressing questions have been left unanswered by Montreal, Kyoto and the other multi-lateral negotiations. The move from fossil fuels to renewable energy alternatives has not been fully considered. At home, India’s growing economy means an insatiable appetite for energy, but it needs to look at its energy policy more carefully. Given the subcontinent’s extreme vulnerability to climate change, this is a battle that will ultimately be fought in our own backyards. So we had better gear up for it.

(This article is primarily based on findings from the IPCC and UNFCC. Other specific studies have been cited when used. Aditi Sen works in the Environment and Socially Sustainable Development (ESSD) Network of the World Bank in Washington DC. The author has written this article in a personal capacity. The views represented here are the author's alone)

InfoChange News & Features, June 2006

Carbon rush

In just the last 150 years, human-induced activity has pushed the level of carbon dioxide in the atmosphere from a comfortable 280 ppm to 381 ppm

99% of the earth’s atmosphere consists of nitrogen (78%) and oxygen (21%). Both these are responsible for complex biogeochemical cycles that support life on the planet. But they play little direct role in regulating climate. The remaining 1% is made up of small amounts of ‘trace’ gases like argon, water vapour, carbon dioxide, nitrous oxide, methane, chlorofluorocarbons (CFCs) and ozone -- all of which are important in the regulation of climate. These trace gases are known as greenhouse or radiatively active gases (those that absorb or reflect infrared radiation).

Carbon dioxide represents just a few hundred parts per million (ppm) of the overall atmosphere, but this tiny component (0.037% of the atmosphere) helps warm the earth to a comfortable level. Too much of this gas in the atmosphere can do a lot of damage, however, because it is CO2 that allows sunlight to stream in but prevents much of the heat from radiating back out. During the last Ice Age, the atmospheric concentration of CO2 was just 180 ppm, freezing the earth. After the glaciers retreated, the total had risen to a comfortable 280 ppm. In just the last 150 years, we have pushed that level to 381 ppm. As a result, the earth is heating up. Of the 20 hottest years on record, 19 occurred in or after the 1980s.

Are increases in trace gases, particularly CO2, the result of people’s activities? The vast majority of scientists believe so. First, the increase is much larger than the natural variability of CO2 concentrations over thousands of years. Second, they know how much coal and oil industrial-age societies have burned and how much forest they have cut down, and these factors are enough to account for the increase. The combustion of fossil fuels like coal, oil and gas, takes carbon that has been locked beneath the earth’s surface for millions of years and releases it into the atmosphere. Third, isotope analysis of the carbon in atmospheric CO2 suggests that much of the increase did come from the burning of fossil fuels. Fourth, complex models of the carbon cycle that represents important processes and feedback between the atmosphere, biosphere and oceans cannot explain the observed changes in CO2 without the human component.

Anthropogenic emissions of carbon dioxide from fossil fuel combustion and cement production reached a peak of about 6.6 GtC/year in 1997 (0.2 GtC/year of that was from cement production) and continues an upward trend, averaging around 6.3 GtC/year over the 1990s, an increase from an average of 5.4 GtC/year during the 1980s.