THE sudden flash floods at the foothills of Gunung Jerai in Yan, Kedah on Aug 18, which claimed six lives and was caused by the headwater phenomenon in the higher altitudes of the mountain, are a grim indication of a possible extreme rainfall event that may be associated with climate change.

Pointing to the possibility of such incidents recurring more frequently in this country, Malaysian environmental experts believe that the headwater phenomenon in Gunung Jerai - attributed to logging activities in the area by some groups - is linked to global warming, the main culprit behind climate change.

The unpredictability of today's global climate and weather system is visibly impacting temperature, rainfall and humidity patterns, to the extent of triggering natural disasters on a more frequent basis.

In July and August this year, excessive rainfall was recorded in other countries, among them being Henan province in China, south Germany, Belgium, Switzerland, Luxembourg, Holland, Austria and Turkey, where massive floods and landslides cost hundreds of lives and extensive damage to properties.

The United States, Canada, Greece and Turkey also experienced extreme heatwaves in the summer months this year with temperatures soaring past 50 degrees Celsius and causing wildfires that destroyed thousands of hectares of forests.

According to the Sixth Climate Change Assessment Report issued by the United Nations' Intergovernmental Panel on Climate Change (IPCC) on Aug 9 this year, greenhouse gas (GHG) emissions from human activities have been responsible for approximately 1.1 degrees Celsius of global warming since the pre-industrial period of between 1850 and 1900.

In fact, IPCC expects the global temperature to reach or exceed 1.5 degrees Celsius of warming over the next 20 years, a major effect of which is extreme weather in the form of sweltering heatwaves, longer summers and shorter winters.

The effects of climate change will vary, with some places, for example, experiencing higher rainfall and others, severe droughts.

Global warming will also see sea levels rising every year, the consequences of which are severe erosion and damage to marine ecosystems.


EXTREME WEATHER

Meteorologist Prof Datuk Dr Azizan Abu Samah expects an increase in the frequency of extreme weather events, particularly thunderstorms and typhoons/hurricanes.

"This is because as the atmosphere gets hotter, its ability to retain water vapour and latent heat increase as well. When the vapour and heat build up, the intensity of the thunderstorm that's generated will increase too," he told Bernama.

In the context of Malaysia, which is susceptible to thunderstorms due to its location in the humid tropics, Azizan said an increase in the atmospheric temperature will lead to the retention of a higher level of water vapour, giving rise to thunderstorms that can generate heavier rainfall and stronger winds.

"Based on this logic, extreme weather, particularly extreme rainfall events that used to have a return period of one to 50 years, will probably recur within one to 20 years," he said.

A return period, also known as a recurrence interval or repeat interval, is the average time or estimated average time between events such as floods and landslides.

In the case of the recent headwater phenomenon in Gunung Jerai in Yan, Environment and Water Ministry secretary-general Datuk Seri Zaini Ujang had explained that the floods resulted from abnormally heavy rainfall of 91 millimetres in the Gunung Jerai area within a short span of one hour and that the return period of that event had exceeded 70 years.

Meanwhile, Azizan, who is director of the National Antarctic Research Centre at Universiti Malaya, suggested several measures to reduce the impact of extreme weather on human life, one of which is the implementation of flood mitigation strategies.

Citing development plans for urban areas, he said when planning the drainage system, the width and depth of the drains should be taken into account to ensure they have the capacity to accommodate the heavier downpours that are expected in the future.

"Similarly, in planning public buildings that have a life span of over 50 years, the effects of climate change should be considered as well, including the rise in sea level or expected increase in the floodwater level so that the buildings can be designed to avert damage inflicted by extreme weather like floods," he said.


EFFECTS OF RISING SEA LEVEL

Azizan also warned that the rising sea level will have a major impact on people, particularly those inhabiting coastal areas.

Any rise in the sea level and subsequent overflow of water will lead to saltwater intrusion which will affect agricultural activities in the nearby areas.

Citing Yan (in Kedah), which is located near the coast, as an example, Azizan said the rising sea level phenomenon would impact its agricultural activities, especially paddy cultivation, following the gradual intrusion of saltwater into the fertile soil beneath the top layer.

As such, he said, the government department concerned should innovate continuously to protect paddy fields located near the coastline against saltwater intrusions.

"The water resources (in such areas) should also be diversified. Drinking water can be sourced, for example, from groundwater such as aquifers," he said, adding that numerous plans can be created to render the nation's socio-economic system more resilient to climate change.

He also called for a change in the government's climate change mitigation approach, the focus of which has so far been land-based. In terms of the Malaysian carbon budget, he said, focus should also be given to coastal and marine ecosystems as they contribute a great deal to the nation's economy and food security.

As a maritime nation whose sea area is more than twice the size of its landmass, Malaysia should consider listing blue carbon - the term for carbon captured by the world's oceans and ecosystems - in its carbon dioxide emission quota, he said.

"The rise in sea temperatures and ocean acidification will have an impact on the productivity of primary marine resources, particularly fisheries and coral reefs," he said, adding that the nation should start observing the sea state such as currents, sea temperature and salinity in order to get a baseline on the situation of the South China Sea, Strait of Malacca and Andaman Sea.

"But how can we observe any change if there is no baseline information? Many of the challenges that arise are linked to the lack of sea state observations."

Commenting on the IPCC report which projects 1.5 to 2 degrees Celsius of global warming in the coming decades, Azizan opined that this range would lead to an acceptable change in the status quo of human civilisation or ecosystems as they can adjust and adapt to the temperature rise.

However, the scenario can change if total concentrations of GHG emissions increase from 400 parts per million (ppm) to 800 ppm, which is expected to result in global warming of 4.0 degrees Celsius.

"If this happens, socio-economic sectors and ecosystems will undergo a complete change, thus creating a situation never experienced by human civilisation - a climate crisis, in short," he added.

Azizan is optimistic that as long as there is no such climate crisis, people will be able to cope with natural disasters as they will adapt to the occurrence of these extreme weather events.

According to him, scientists are of the view that limiting the rise in global temperature to the 1.5 to 2 degrees Celsius range will have less detrimental effects but to keep global warming within this range, there must be reductions in GHG emissions. However, the targets for these reductions have yet to be achieved and this is the climate crisis mankind is facing now.

Azizan said while technological advancements in planetary geoengineering can slow down global warming, the looming climate crisis, however, cannot be tackled alone by individual nations. Instead, the world needs new paradigms for joint efforts to sustain the environment.


STRENGTHEN WARNING SYSTEM

Universiti Putra Malaysia Department of Environmental and Occupational Health lecturer Associate Prof Dr Haliza Abdul Rahman echoed Azizan's views, saying that human activities are a major contributor to the rise in GHG concentrations which have a bearing on the earth's temperature.

The rise in temperature occurs when the residual heat pouring into the climate system exceeds that released into space.

In Malaysia, global warming effects are evident in terms of the unpredictability of its climate and weather system, she said. Its rainfall pattern, for instance, no longer tallies with the season. In fact, at times there have been incidences of weather extremes that caused flooding and landslides, such as the one in Gunung Jerai, Kedah recently.

Haliza said the erratic rainfall pattern can disrupt agricultural activities which will not only affect the incomes and livelihoods of farmers but, ultimately, also the nation's Gross Domestic Product.

Among the measures that can be taken to reduce the impact of the disruptions brought about by the unpredictable weather are strengthening the early warning system for rainfall and mapping areas that are potential disaster zones.

"We already have an adequate warning system for rainfall but it needs to be strengthened, in particular the system of delivering information to stakeholders in the 'problem' areas.

"Furthermore, equatorial nations like Malaysia experience what we call convective cloud weather. Sometimes, just as we detect it and want to issue a warning, the weather clears up. And, there are times when we don't have enough time to issue a warning. These are among the difficulties faced in predicting the weather, such as rainfall, in small areas like Yan, Kedah," explained Haliza.

She also proposed that efforts to reduce GHG emissions in Malaysia be further streamlined, including increasing the number of low-carbon cities and improving the public transport system.

She said it should also be made mandatory for companies in all economic sectors to calculate their GHG emissions and submit a yearly report to enable the government to identify the sectors that need to be focused on.

According to the Paris Agreement, a legally binding international treaty on climate change that came into force in November 2016, Malaysia has pledged to reduce GHG emissions to 45 percent by 2030, compared to 40 percent previously.

Global carbon emissions are currently estimated at 36 billion tonnes a year but the figures are expected to rise gradually worldwide after the end of the COVID-19 pandemic.

-- BERNAMA