ISSN: 1391 - 0531
Sunday February 24, 2008
Vol. 42 - No 39

‘Too darn hot’

By Dr. Sriyanie Miththapala

The other day, my friend Ranjit Galappatti said facetiously that he intended lying on an easy chair for the rest of the day to exhale less and thereby minimise his carbon dioxide emissions, so that he could help mitigate the impacts of climate change. Jokes apart, it seems that thanks to Al Gore and Alfred Nobel, global warming and climate change are on everyone’s lips these days.

So what is all this fuss about? What, in fact, are global warming and climate change?

Between 1970 and 2004, the annual emissions of carbon dioxide (CO2) grew by about 80%, and during the last century, the concentration of CO2 in the atmosphere has risen by twelvefold. Increased emissions into the atmosphere of CO2 and methane (CH4) – so called greenhouse gases (GHG) - cause a distinct warming of the earth. These gases function much like glass panes in a greenhouse, allowing light in, but preventing heat from escaping. This greenhouse effect, as it is called commonly, is important: without it, the earth would be too cold for humans to live. The problem is that now there is just too much GHG, making the earth too hot. Records show that the 1990s were the warmest decade in a century and that 2005 was the hottest year ever on record.

The Intergovernmental Panel on Climate Change (IPCC – the joint winner with Al Gore of the recent Nobel Prize for peace) predicts that for the next two decades the earth will warm about 0.2°C per decade; and even if GHG are kept constant at levels of year 2000, the earth will still warm about 0.1°C per decade.

Given that in evolutionary history the earth alternated between being cold and warm, what is the big deal about a teeny-weeny little warming when we swelter anyway in the tropics?

Firstly, the speed at which we are spewing out GHG has increased dramatically in the recent historical past. Since the time of the industrial revolution, through our excessive use of coal and oil, our innumerable vehicles that guzzle and burn petrol, we are spitting out enormous quantities of CO2 into the atmosphere, with the USA and China vying for first place as the largest emitters. The IPCC Special Report on Emission Scenarios projects an increase of global GHG emissions by 25-90% between 2000 and 2030.

In the meantime, we are heaping mountains of trash and garbage as solid waste and rearing millions of herds of cattle and sheep – which generate huge quantities of CH4.

In short, we have increased hugely our carbon sources - i.e, systems containing carbon that has more carbon flowing out of it that into it. Meanwhile, we are cutting down forests at the rate of the size of two American football fields per second. In the process of making their own food, green plants take in CO2 and release oxygen – so vital for our respiration; i.e., they function like carbon sinks that absorb CO2. Losing forests means that this CO2 is not absorbed from the atomosphere. In fact, about 20% of global greenhouse gas emissions currently come from clearing the world’s forests. So while we increase our carbon sources, we are depleting our carbon sinks.

The result is that we are worsening the greenhouse effect – making the earth warmer and warmer. The second reason for all this fuss is that this warming, little though it may seem to many laypersons, is causing profound changes in the earth, including climate changes.

Glaciers in Polar regions and on mountain tops are melting as a result of this warming. In 2002, NASA confirmed that the Arctic ice had lessened by 2.7% per decade.

Associated with melting glaciers is sea level rise, putting at risk much of the population of Asia (over half of the population of Asia lives near the coast). Low-lying coastal areas such as the Maldives, Bangladesh and Mumbai are expected to flood from this increase. It is estimated that in India alone, millions of people are at high risk from sea level rise.

Sea level rise will also affect coastal ecosystems. It will retard the growth of corals, change the composition of species in coastal ecosystems and reduce their ability to provide us with food and shoreline protection.

It has been observed that snow caps on mountain tops – such as Mt. Kilimanjaro in Africa and the Himalayas in Asia – are melting faster and decreasing in size. The former has already retreated 75% during the last century, losing 80% of its water. It is predicted that by 2030, the snow caps on the Himalayas (the largest glaciers outside the Poles) could be reduced by about 80%. In the short term, rapidly melting glaciers means intense flooding downstream, but in the long term, the reduced quantity of ice produces less freshwater downstream. The snow melts of the Himalayas feed the Ganges, Indus and Brahmaputra. The Ganges – which alone provides water to 400 million of people – is predicted to lose two-thirds of its water as a result of climate change.

Coastal flooding will result in salt water entry into fresh water bodies. This will damage fresh water supplies for coastal communities and affect livelihoods and human well-being. In China and Bangladesh, the effects of sea level rise and salt water intrusion are already damaging their economies and environments. Salt water intrusion into lagoons, estuaries and mangroves will damage them, affecting the services - such as coastal fisheries, flood regulation and storm protection – that they provide us.

Global warming is also affecting the mighty oceans. Higher ocean temperatures are affecting marine organisms – decreasing in particular, microscopic organisms called phytoplankton, which make their own food and form the base for all food webs in the oceans.

Warming is also changing El Niño patterns. El Niño in Spanish means ‘the little boy’, referring to the Christ child, because this event is usually noticed around Christmas time. El Niño is an interaction between the atmosphere and ocean in the tropical Pacific Ocean that has hugely important consequences for the world’s climate. In normal, non-El Niño conditions, the winds and ocean currents work in such a way that there is warm water near the Indian Ocean, Indonesia and Australia and cool and nutrient-rich waters near South America. During El Niño, the winds weaken and air pressure changes causing rainfall in normally dry areas and drought in normally wet areas (such as in the Indonesian archipelago) and spreads warm water to the Pacific Ocean. The surface temperature of the sea increases by about 0.5°C. Historically, El Niño has occurred at irregular intervals of 2-7 years and has usually lasted one or two years, but climate change is now increasing its frequency.

Coral bleaching – mass scale die- off of corals has already occurred worldwide in 1998 as a result of warmer water currents brought by an El Niño event. In 1998, 16% of the world’s coral reefs and 50% of the Indian Ocean’s coral reefs were bleached. This means that the nearly 500 million people who depend - directly or indirectly – on coral reefs for their livelihoods and to live would have been affected some way or another.

Overwhelmingly, global warming is affecting the global climate. Rainfall patterns have changed. In some places, it rains more, in others, it rains less. In South Asia, the south west and the north east monsoons – which overpoweringly affect human well-being and drive agricultural patterns in the region, have become unpredictable. It is now raining less frequently but much harder when it does, increasing the impacts of flooding, and with it, the devastating effects on lives and livelihoods. During the monsoons of last August, over 19 million people were displaced in India and Bangladesh.

If too much rain is a problem in some areas, drought is a problem in yet others. Parts of Africa and Central Asia already face a high degree of water stress. Many of the countries here are land locked and receive little rain. When climate change reduces rainfall still further, there are acute water shortages (for agriculture and drinking), increased dust storms and desiccation of vegetation.

In 1995, 1400 million people lived in areas in drought conditions. Projections with different climate change scenarios predict an increase of 364 to 1661 million people living under conditions of water stress by 2020.

Global warming has another horrifying impact on the world’s climate: it is increasing natural disasters. It is estimated that during the last few decades, an average of 250 million people have been affected each year, with nearly 58,000 deaths as a result of natural disasters. In 2004 alone, natural disasters affected the lives of about 140 million people.

Climate change has associated economic costs that are terrifying. Hurricane Katrina which hit the eastern USA cost a staggering 81.2 billion USD; it is predicted that climate change impacts in the extent of arable lands will have economic losses of 56 billion USD, indubitably increasing the number of hungry people in the world.

Climate change has substantial impacts on the balance of interactions between species in ecosystems. Warming temperatures are changing the patterns of the flowering of plants in the spring, colour changes of plants in autumn, migration of animals, hatching of young and animal hibernation. For example, the Pied Flycatcher, a bird in Germany, reacting to the length of day rather than temperature, arrives back home at the usual time in spring. But the caterpillars that it feeds to its chicks are breeding much earlier - cued by the warmer temperature. The result is that the Flycatcher has to nest much earlier so that it has enough food for its young. If the earth warms more, and the caterpillars breed earlier and earlier, but the flycatcher returns at the usual time, this particular interaction between predator and prey will be disrupted.

Similar interactions – such as those between pollinator and pollinated species or predator and pest species - may be crucial for agriculture. When these links are disrupted, commercial crops will be damaged.

Further, warmer temperatures are affecting the natural range, distributions and densities of many species. Some tropical species are expanding their ranges into temperate areas, while species adapted to the cold are finding that ‘it is too darn hot’ for them. A startling projection reveals that 20-30% of species from different regions may become extinct if warming exceeds 1.5-2.5°C. These irreversible changes, ultimately, will change the composition of ecosystems.

With the warming of the earth, mosquito species have expanded their ranges so that mosquito-borne diseases such as malaria are spreading to higher altitudes in Asia, Central Asia, Latin America; dengue to Mexico; and yellow fever to Colombia.

Although climate change will have overarching effects worldwide, it will have disproportionate effects on Asia. Asia is the world’s most disaster prone region, having suffered about half of the world’s major disasters over the past fifty years. Climate change could cripple Asia, already stressed with overpopulation, poverty, internal conflict, resource overuse and spread of disease.

Coastal communities and ecosystems are more at risk from climate change than people and habitats inland. Among all communities at risk, the poor - already lacking of the basic amenities of life – are usually the hardest hit by natural disasters. Among the poor, women and children are more at risk from climate change than men. Out of 1.4 billion people in the developing world who live below the poverty line, 70% are women. Women in southwest Bangladesh must walk 5-6 km every day to collect drinking water. When salt water entry into fresh water as a result of climate change exacerbates the lack of fresh water during the dry season, it is the women who have to bear the burden of walking longer and longer distances to find it.

Next week: what can we do to combat the impacts of climate change?

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