Socio-environmental impacts of climate variability. Droughts in Venezuela -

Socio-environmental impacts of climate variability. Droughts in Venezuela -

By Geog. Karenia Cordova Saez

The possible relationships between climate change and variability are and have been the subject of numerous scientific discussions, due to problems of statistical reliability of climate records or the absence of them.

Concern about climate variability and its influences in terms of alterations in rainfall patterns, temperatures and other parameters, has been increasing, particularly since the 1990s, as a result of the Climate Change Conference in Kyoto .
The possible relationships between climate change and variability are and have been the subject of numerous scientific discussions, due to problems of statistical reliability of climate records or the absence of them.

This necessarily implies resorting to estimation techniques, which are not useful to visualize changes in the climatological parameters attributable to climate variability or change. To improve these levels of uncertainty and better diagnose levels of vulnerability to climate variability or change, the International Research Institute for Climate Prediction (IRI) at Columbia University has developed complex prediction models based not only on atmospheric data , such as those commonly used in short-term weather forecasts, but also in data from ocean and satellite sensors.
These models mathematically simulate the interactions of land, oceans and air, which together determine the planet's climate. The reliability of these models is due to the fact that "they are based on a set of scientific observations and well-established physical laws, among which are included the laws of gravity and the movement of liquids, of the conservation of momentum energy. , mass and water "(GOMEZ ECHEVERRI, pp. 19, 2002).

Thanks to them we can obtain fairly reliable forecasts of climatic parameters relevant to human activity, such as rainfall, relative humidity, temperatures, etc., all of which is of vital importance in the scenario of climate change uncertainty, since theoretically It would be possible to reduce vulnerability to extreme events, such as prolonged water deficits or severe droughts, or excess water, represented by storms and high-intensity floods.

In the maps presented below, the percentage of rainfall observed above or below the normal ranges expected for the February-March-April 2003 quarter, produced by the Center for Climate Predictions, of the NOAA (National Oceanic and Atmospheric Administration. US Department Commerce).

In the image it is observed, how effectively the north and south-eastern region of the country, the area where the Guri dam is located, the most important hydro-generation system in the country, was affected by a deficit of 50% or more in rainfall. We also observe vast regions of the north-central area of ​​the country, where it rained only 75% of what was expected, while towards the central-western region there are surpluses of over 120% of rainfall (Fig. 1).

The probabilities of precipitation, estimated by the IRI, for the quarter of May, June, July 2003, based on the records reported during the month of April, 2003 and the simulations of the model, tend to confirm these trends. In Figure 2, below, it is easily observed how almost the entire country will be affected by a rainfall deficit, more severe towards the north-eastern region, with about a 50% probability below the normal regime of the rains, in dark brown, while for the north-central and north-western region a 45% rainfall deficit is estimated in orange.

In the rest of the country in general, 40% less rainfall is expected, all of which should alert the authorities that administer water resources, either for human consumption or for hydro-generation, about the possibilities of critical restrictions in supply. of the resource. (Fig. 2)

However, due to climatic variability, it is necessary to permanently monitor this situation, given that the forecasts that at the beginning of the year pointed towards a predominance of conditions favorable to El Niño, which in Venezuela is associated with a water deficit, are changing in the second semester towards conditions favorable to the La Niña phenomenon (Fig. 3). The forecasts at the end of June will be essential to determine the trends of the rainy season, as well as the resource management strategies.

Source IRI, Enso Update, May, 2003.

Bibliographic references.

- GOMEZ ECHEVERRI, Luis. Climate Change and Development. UNDP Regional Office for Latin America and the Caribbean, Yale School of Forestry & Environmental Studies, San José, Costa Rica, 2002.
- CLIMATE PREDICTION CENTER, Regional Drought Maps. National Weather Service, NOAA, May, 2003.

* Prof. Karenia Córdova Saez.
Institute of Geography and Regional Development Area of ​​Energy, Environment and Sustainable Development.
M.Sc. Planning Energy Systems.
Central University of Venezuela.
[email protected]

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