Saturday, April 21, 2007

El Niño, Rising Waters Create Climate for Destruction

El Niño, Rising Waters Create Climate for Destruction
Growing Link to Natural Disasters

By Allegra N. LeGrande, Ph.D.
NASA Goddard Institute for Space Studies and Center for
Climate Systems Research, Columbia University, New York, USA

The children served by Orphans International Worldwide predominantly live in poor, tropical countries. These countries are already experiencing climate change – the tropics had about 0.4°C (0.72°F) of warming since 1950 – compared to 0.6°C (1.08°F) worldwide. The wealth of different regions will influence ability of each to deal with changes – since poorer areas of the world are more dependent on local resources and have less free capital to mobilize in the case of hardship, they are particularly vulnerable to climate change. Areas in the tropics, in particular, will likely have more negative impacts as a result of climate change than positive. The stresses placed on these nations will certainly affect these children, as well. I will summarize a few points on climate change of particular importance to the tropics.
Greenhouse gas emissions are likely to cause between 1.5 and 4.5°C (2.7-8.1°F) of warming over the next century according to the Intergovernmental Panel on Climate Change, 4th Assessment Report (IPCC AR4). Initially, the warming will continue at a rate of around 0.2°C (0.35°F) each decade.

Climate is the foundation that sets the stage for the weather we experience every day. Individual extreme weather events cannot be directly tied to climate change. However, extremes are by definition, phenomena that are beyond the norm. Climate change will alter the ‘normal’ for each region. Future human-induced climate change is likely to occur at a rate that exceeds many regions ability to adapt. Many countries in the developing world have a smaller adaptive capability than wealthy nations, making it even more difficult for them to address the effects of climate change.

Media attention has focused on two issues: intense tropical storms and sea level rise. Researchers are still investigating exactly how great the link is between these two phenomena and climate change.

Hurricanes: Briefly, it is not possible to link any particular extreme tropical storm to climate change; however, empirical evidence suggests that when conditions are right for the formation of a tropical storm, it will likely to achieve greater intensity as a result of climate change. These storms will have greater higher wind speeds, storm surges, and amounts of precipitation, and thus be capable of causing greater damage.

Sea level: Sea level rise over the next century will be at least 10-59 cm (4-23 in) according to the latest IPCC report. Sea level rise at this pace (10 cm or 4 in per decade) could be devastating to low-lying coastal areas not only because of land loss, but also because of salinization of low-lying freshwater resources. Coastal erosion may also accelerate (not only because of climate changes, but also because of land use changes). Besides these two widely reported affects, the developing world will almost certainly have many other impacts from climate change.

Rainfall: The water-cycle (hydrologic cycle) is likely to intensify meaning greater frequency of drought and flood events. These extremes of drought and flood are likely to cause problems to much of the developing world. Semi-arid regions are particularly at risk for drought which will likely cause lower crop yields and greater likelihood of malnutrition. Areas already very moist will likely have even greater rainfall, and perhaps flooding.

Temperature: Temperature extremes will affect not only people, but also their crops and livestock. Heat waves become more common, and these can directly lead to deaths. Heat waves may also cause decreased crop yields in areas that are already warm, as well as increased fire likelihood. Areas that rely on freshwater from the melting of snow (e.g., Asian communities whose rivers are fed by Himalayan snow-melt or South American communities whose rivers are fed by Andean snow-melt, etc.) are likely to see flood events as the snow melts too quickly early in the season, then drought and shortage as less water (snow pack) remains later in the season.

Climate change is a very serious issue in the developing world. We can take two tracks to addressing it. First, in the developed world, we must reduce our greenhouse gas emissions – this will entail investment for the development of new carbon-neutral technologies and techniques. Second, we can educate the children of developing countries so that as their countries progress, they adopt better, more sustainable technologies and become part of the solution for preventing problematic future climate change.

The above appeared in the April edition of the InterNews (vol. 4., no. 4) and was been condensed due to space limitations. The newsletter is available at For a pdf of the full scientific document including tables authored by Dr. LeGrande, please e-mail

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