What effect will global warming have on Thailand
14 april 2008
By Chang noi
Over the last three years, most scientists and most political leaders have reached rough agreement on climate change at a global level. The UN’s Climate Change panel showed the world has got one degree hotter in the last century, and the trend is accelerating. Sea levels are rising. Weather is changing. Things will get worse. Since the UN panel reported last year, most of the criticism and new research suggests its analysis was too conservative.
So what will this mean for Thailand? Over the last twenty years, the average temperature has trended upwards by about one degree. What will happen next? The changes we can expect are fairly clear, though the timing is uncertain because prediction is very complex, and because much depends on what happens elsewhere in the world.
First, the good news. Warming is going to happen quicker near the poles rather than the equator, and over big land masses rather than near the sea. Isan may get a bit hotter. But generally Thailand will warm slower than elsewhere.
Overall the world will also get drier. Here again, Thailand either escapes the worst, or at least the picture is unclear.
The peninsula will get wetter. Over the rest of the country, some models predict more rain and some predict less.
But the rainfall will become more erratic. The wet season will be wetter, and the dry season drier. There will be more flooding and flash flooding from huge downpours, and more drought and shortage outside the monsoon season. Variability from place to place will increase, with one province swamped and its neighbour parched. Variability from year to year will also be more wayward. The dry El Nino years will be drier, and the wet La Nina years will be wetter. In short, both more floods and more droughts will make water management much tougher. (It’s pretty obvious this is already happening).
That much seems certain. But there is also a black hole in our knowledge about likely climate changes in this region. The sun warms the earth most in the tropics. That heat is circulated elsewhere by massive sea currents. Nobody is sure how these might change. Because the Gulf Stream in the Atlantic is crucial to keeping Europe warm, there has been a lot of research about it. The results are cautiously optimistic. But on Nino-Nina, almost nothing is known. The current is interlinked with the monsoon, but how this whole complex will be affected by global warming, nobody seems to know.
Global warming is already melting the Himalayan glaciers which feed all the great rivers of Asia, including the Mekong and Salween. As this melting gets worse, the river flow will initially increase, contributing to floods. Later the flow will diminish, exacerbating off-season droughts. This is another area where predictions are very vague.
Warming will raise the ocean levels. The UN’s (conservative) prediction is a rise of 20 to 80 cms in this century. In Thailand, this will not flood much land, but will cause salination along the lower reaches of all the waterways of the lower delta. It will also increase seasonal flooding in Bangkok and other towns. The OECD ranked Bangkok seventh in the world among cities where climate change will affect people and property.
Here again there is a black hole of knowledge. This prediction of rising sea levels is based almost wholly on thermal expansion of the volume of water. But what happens when the great ice sheets of Greenland and Antarctica melt? Nobody is quite sure. Some predict it might raise the sea level by another 5 or 7 metres. Then the water will be up to the second-floor windows in Bangkok, and Suvarnabhumi terminal can be put to the use for which it seems to have been designed, as a horticultural greenhouse.
Salination will affect some very valuable agricultural land. But overall, the impact on Thailand’s agriculture seems moderate by global standards. In temperate areas, crops are highly sensitive to changes in heat and moisture, so climate modelers predict big falls in output in the temperate zone. But year-to-year variation has always been a feature of monsoon-based agriculture. Crops have learnt to be reasonably tolerant, and the impact should be less.
There are many other impacts, especially through disease (the recent resurgence of malaria and dengue may be a forerunner). But overall, the prospects for Thailand do not look too bad. Or, to put that another way, many other places will be devastated before Thailand. But this is the point. The impact of global warming on Thailand will not come so much from the direct physical changes, as from the social and economic overspill from elsewhere.
Thailand is surrounded by places that are right on the sharp end of climate change. Bangladesh faces the same rainfall changes, ocean rise, and glacier melt effects detailed above. But because it has 100 million people practicing precarious agriculture a few centimeters above sea level in the delta of a great Himalayan-glacier-fed river, the impact will be disastrous. Vietnam’s rice bowl in the Mekong delta is similarly vulnerable. Nobody knows what will happen to the delicate flows of the Tonle Sap which sustain Cambodia.
Northwest China already has a severe water shortage. It is also destined for higher temperatures and lower rainfall, and hence will be another early disaster zone.
The debate on climate change is (quite rightly) dominated by natural scientists and focused on physical changes. But the ways these changes play out will be through economic, social, and political processes. Markets anticipate change. People fight for resources, or migrate for survival.
The current crop price chaos is an early ripple. Europe has recently realized that one of the first impacts will be “climate migrants.” Here in Thailand, the recent intrusion of Rohingyas, originally from Bangladesh, is another early ripple of a bigger wave.
Before Thailand burns up or sinks beneath the waves, it will be hit by the economic and political overspill of climate change.
Source : The Nation
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