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Global Trends by Martin Khor

Monday 19 January 2015

Lessons from the great floods

The recent great floods should be treated as a “new normal” linked to regular weather extremes, and an all-round plan and system should be established to curb the causes and effectively manage the disasters

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The first half month of 2015 has seen Malaysians pre-occupied with the big clean-up following the big floods that swamped many states, especially in the East Coast.

It will take some time to get the houses, schools, hospitals, offices, roads, drains, railway tracks, back into pre-flood shape. 

The costs of doing so are staggering, with each initial figure exceeded by new estimates. The total will run into many billions of ringgit.  The government will foot the bill for repairing public facilities; and there is some government and spirited public help for flood victims’ personal losses. 

But the affected people will still bear immense suffering and losses, for example of lost business and livelihood income on top of the lost household belongings.

It is time to learn the lessons and prepare for the future.  Hopefully a high-powered coordinating council will deal with all aspects of analysing the causes of the floods and how severe we can expect future floods to be, of minimising the causative factors, preparing better to mitigate future events, and preparing to manage them more effectively when they inevitably happen again. 

Recent events and climate science strongly indicate that the 2014 downpour and floods are not one-off events but part of a national, regional and global pattern linked to climate change and extreme weather events.  And that we can expect the situation to worsen, more and more, in future years and decades.

Malaysia has experienced increase in temperature, consistent with the global warming trend, according to data in a 2012 paper by Yap Kok Seng, then the head of the Malaysian Meteorological Department (MMD), and his colleagues.

The global temperature increase has led to changes in weather including major wind patterns, amount and intensity of precipitation, and increased frequency of severe storms and weather extremes, according to the paper, “Malaysia Climate Change Scenarios”.

Malaysia has experienced more extreme weather events over the past decades, as well as an increase in weather extremes, says the paper, backed up by graphs and statistics.

This increase could be associated with the natural variability in the sea surface temperatures of the equatorial Pacific Ocean (El Niño/La Niña events) and the Indian Ocean (Indian Ocean Dipole).

For example, the Northeast monsoon of 2006/2007 and 2007/2008 brought torrential rain and floods to Malaysia, with the Northeast Monsoon rainfall in 2006/7 being the worst ever recorded over the southern part of the Peninsula, especially in Johor, causing the worst floods.

“Other extreme events such as severe thunderstorms, dry periods and haze have become more prevalent over the recent years. Due to the complex interaction of the atmosphere, ocean and biosphere, the global warming definitely has contributed to these changes, with climate variability and global warming acting in the same direction over the period.”

The paper points out that as the climate changes due to global warming, therefore, sea surface temperatures (SSTs) also continue to increase.  Higher SSTs are generally accompanied by increased water vapour in the lower troposphere, thus the moist static energy that fuels convection and thunderstorms is also increased. Most of tropical rainfall, as experienced in Malaysia, is from the thunderstorm activities.

According to the MMD analysis, Malaysia has experienced the following changes:

  • Since 1980s there have been increasing number of days of extreme rainfall events.
  • The number of days with extreme wind events have also increased at several stations.
  • The Peninsula, Sabah and Sarawak have seen increase in the number of annual thunderstorm days.

 

The paper indicates that the northeast monsoon and the southwest monsoon have become more intense.   Annual rainfall data for the period 2000-2009 compared to1970-1999 show an increase in rainfall for most parts of the Peninsula (except the central part) and Sabah and Sarawak, and the major increase has occurred in the past 5 year period of 2005-2009.

The regions with the most increase in rainfall are the northeast coast and northwest coast parts of the Peninsula, central coast of Sarawak and north Sabah.

Interestingly, the paper also finds that there are also more frequent and intense dry years (in 1975-2005 period compared to 1951-75), which are only partly due to El Niño events.

It thus appears that the new weather pattern in Malaysia includes both heavier rainfall and dryer spells, even within the same year.  This explains the co-existence of no-rainfall months causing water shortages in various states, with high-rainfall and flooding months in other states or even the same states.

The lesson from all this is that we have to pay much more attention to increasing extremes and extreme events in the weather, counter-act their causes, and deal with their effects. In climate change terms, this means having plans for mitigation, adaptation and loss-and-damage.

While in the short term we can do little to alter weather patterns, we can certainly do a lot to prevent making the situation worse.  

Top on the list is to stop further deforestation.  The widespread chopping of trees especially in highland areas is a major reason why the intense rainfall causes so much flooding.

The natural tree cover breaks the falling rain and allows the gentler drip of water to seep into the ground, providing ground-water to flow into the reservoirs.

When trees are removed, the rain falls heavily onto the ground, removes the soil, and the water plus the soil is swept into streams and rivers, which get clogged up with soil and which are also filled quickly with the high volume of rain water.

The damage begins in the upper reaches of the river and is transformed into devastation as the engorged rivers reach the town areas, breach their banks, and the raging waters sweep along houses, cars and everything else in their way.

After each disaster, promises are made to stop deforestation and to disallow highland development.  But after a few months and years, the logging and development works begin again, causing even more damage the next time there are heavy rains.

This time, the situation has got so serious, the public expects firm and effective action from all levels of government and all relevant agencies.

Besides conserving the forests, there are many other ways to mitigate and adapt better.  These include replanting of trees in deforested areas; soil conservation as a strategy and major activity all over the country; de-silting of rivers and streams; the vast improvement of drainage in urban and rural areas; climate-proofing of buildings, including building new schools and houses on stilts or on pillars in flood-prone areas; protecting coastal areas from storms, winds and high waves including through conserving and replanting mangroves.     

There is also the whole set of activities for better management of floods and other disasters, including establishment of permanent evacuation centres; early warning systems; earlier and better systems of evacuation; stocking and distribution of food, clean water, medicines and other essentials to victims; plans for repair and rehabilitation; and the up-front allocation of financing.

If we treat the “great floods” not as once-in-20 years or once-in-a-lifetime events, but as part of the “new normal”, then the plans for a better eco-system and for managing the disasters can be made more systematically, and a significant budget for regular financing can also be set aside.

Let’s hope that we do learn the lessons of the recent great floods and prepare comprehensively to prevent, mitigate and manage them effectively.  We may not be able to achieve “Never the floods again”, but we must achieve “Effectively manage the heavy rains and floods that are sure to come.”  

 


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