Time to get serious on climate change

Basil Fernandez, Contributor

The extreme rainfall event that took place over the Eastern Caribbean, December 24 and 25, occurred outside the annual Atlantic hurricane season that lasts from June 1 to November 30.

The event led to catastrophic damage in St Vincent, St Lucia and Dominica.

Climate change was stated to be the cause of the event and associated damage.

However, apart from reading of the damage and the cost to the economies of the small island states, there has been no scientific assessment of the rainfall and the cause of the high-impact damage.

It is critical that this scientific assessment be done if there is to be no repeat of the damage, as the projections from climate change models are for more severe and intensive weather systems across the Caribbean.

There are many lessons that must be taken from this event.

First, the islands must be prepared for extreme weather events at all times - in or out of the hurricane season. The resilience to intensive rainfall, resulting from climate change, whether of short or long duration, has to be a primary objective of the entire Caribbean.

Second, the monitoring and forecasting capability of the meteorological and hydrological agencies must be upgraded and expanded to provide early warning, and to collect data on the event for assessment, analysis, and the implementation of strategies, and work to build the resilience.

It was stated that mal-functioning equipment prevented forecasting of rainfall associated with the low-pressure system.

Communicating with colleagues in St Lucia about the rainfall, it was revealed that the gauges were lost so there is no measured record of the rainfall.

However, satellite estimates of rainfall show 200mm of rain fell over St Lucia, 76mm over Dominica, and 124mm over St Vincent.

No return periods were calculated. It must also be noted that Grenada had rainfall of over 100mm whereas Martinique had 76mm from the same event. No information is available on damage in either of the two islands. Again, it must be noted that these rainfall amounts are estimates and may be an overestimation.

Clearly, the case for a reliable monitoring network has been made by this extreme event. Governments of the region must provide the resources to maintain and upgrade hydrological and meteorological networks if catastrophic impacts on GDP and economic development are to be avoided.

Jamaica's system

The Planning Institute of Jamaica has been instrumental in the development of the World Bank-funded 'Improving Cli-mate Data and Information Man-agement Project (ICDIMP)' that has as its main objective, "the improvement of the quality and use of climate-related data and information for effective planning and action at local and national levels".

One outcome will be "the upgrading of national equipment and systems for improved collection, processing of data and more accurate forecasting of hydro-meteorological events including extreme weather events."

Third, YouTube videos and news clips of the damage indicate the following:

A high degree of wooded material (bamboos and trees branches/trunks) deposited in the affected townships and drainage systems blocking flow paths. This is similar to the occurrence on the November 10, 2012, flooding of Port Maria, two weeks after the passage of Tropical Storm Sandy, which deposited wooded material in the drainage systems and which were not cleared prior to the extreme rainfall event and so compounded the flooding.

Debris flows, consisting of rocks of all sizes and soil, that led to the blockage of drains, roads, and damaged houses. The islands of the Eastern Caribbean are all volcanic in origin and with a high degree of faulting and fracturing of the rocks as a result of tectonic activity. Once saturated, the rocks are very vulnerable to landslides and slippages. The determination of the landslide-risk vulnerability is critical to the location of developments, main-tenance of slope stability and drains to move water away from the vulnerable areas.

The blockage of drains by wooded material, debris flow, and motor cars that acted as dam walls preventing flow, and leading to overtopping of channels and bridges, and the loss of sections of roadways. Climate change requires that the capacity of drainage systems be reviewed and adaptation be done to safely carry the runoff from the projected increased intensity of storms.

Basil Fernandez is managing director of Water Resources Authority. Send feedback to columns@gleanerjm.com

Governments of the region must provide the resources to maintain and upgrade … networks if catastrophic impacts on GDP and economic development are to be avoided.