Deputy director of the National Centre for Hydrometeorological Forecasting Le Thanh Hai spoke to Viet Nam News about the influence of El Nino and climate change on Viet Nam.
Winter this year is warmer than previous years. What is your opinion about this phenomenon? Is it caused by El Nino? How about the impact of El Nino in other countries in the area?
The temperature in winter this year is 1 to 2 degrees Celsius higher than in previous years. And the number of north-east monsoon spells is also less than the previous years. Normally, since October, about three to four north-east monsoon storms will occur per month causing cold weather but this year few cold spells have occurred. In October this year, several areas in the north still experienced hot days.
Due to climate change making the Earth warmer, few severe cold spells have occurred recently and the cold spells last a shorter period. In 2008, the cold spell lasted for more than a month, but in some recent years the cold spells only last about five to seven days, or even three to four days. The Lunar New Year festival, which will fall in the beginning of February next year, is forecast to be warmer than other years. During the nine-day festival, about three to four days will be cold.
El Nino is the reason for the weather phenomenon. At present different hydrometeorological forecasting centres in the Asian-Pacific area said that the El Nino could be more and more severe in the future.
The latest forecast of international hydrometeorological forecasting centres said that El Nino could last until the end of winter this year, or even until the end of spring next year. Thus it is possible that El Nino 2015-16 can be the longest El Nino during the past 60 years.
El Nino has affected Viet Nam via severe weather. Can you tell more about the problem?
The El Nino's expression this year is clear. The first one is the amount of typhoon and tropical pressure. During the typhoon season this year, the north-west area of the Pacific Ocean saw a lot of typhoons but few typhoons came to the East Sea. This year the East Sea saw five typhoons and two tropical pressures. In 2013, we saw 18 typhoons. Thus this year the number of typhoons has been only about one third compared with 2013.
Besides, the temperature is higher than the average level of other years. Summer this year is very hot and many hot temperature records were broken whereas rainy season started late and ended early with little rainfall.
The rainfall in the Central Highlands, southern and northern areas is also less than previous years. Last year the rainfall reduced by 10 per cent and this year it reduced by 20 per cent to 40 per cent. As a tropical country, Viet Nam will have a lot of difficulties if the rainfall is limited.
Drought in the southern provinces of Ninh Thuan and Binh Thuan and the central provinces of Khanh Hoa and Phu Yen also started in previous rainy seasons. The rainfall in the provinces in the last rainy season reduced by 60 per cent. And then the rainy season this year had little rainfall.
In central provinces, typhoon and tropical pressure contribute about 40 per cent of the total fresh water. If the provinces see fewer typhoons, they will lack fresh water. Only two typhoons affected central provinces in 2014 and 2015 so the area lacks water.
El Nino also caused a severe contrast between different areas in the country. For instance, Ninh Thuan southern province sees drought while Quang Ninh northern province sees record rainfall of 1,600mm. And Sa Pa Town in the northern mountainous province of Lao Cai sees severe cold in summer with the temperature of 12 degree Celsius in July.
Flood season in the Cuu Long (Mekong) Delta this year came late. What is the reason of the phenomenon? What is your warning about the flood conditions in the coming time?
The Mekong Delta often sees flood season in October with the average water level of 3m. But this year the water level in the area is very low, about 1m to 1.5m lower than the average level. It is an unusual phenomenon which was acknowledged once in 1926.
The reason is the water shortage at the upper reaches of the delta. Water must fill up the Tonle Sap Lake in Cambodia before coming to Viet Nam. But this year different areas saw little rainfall so there was only enough water for the Tonle Sap Lake.
Due to the lack of water, salt penetration is serious affecting the environment and daily life of local residents.
The centre gave a warning about the phenomenon since its early stages and now gives warnings about salt penetration every two weeks.
The centre warns that the coming dry season will be severe due to salt penetration, water shortage, many sunny days and few cold spells. The phenomenon can cause forest fires and environmental pollution. Drought in the southern province of Ninh Thuan and Binh Thuan in coming years can be much more serious than this year.
What is the centre's recommendation to prevent and limit the consequences of El Nino?
The centre has supervised El Nino's development to give update warnings and forecasts to concerned organisations and residents.
Policy makers, typhoon prevention and control steering committees and farmers should keep close watch on the weather forecast to update the latest development and have fast preventative measures. Whirlwinds must be updated every hour, typhoons must be updated every day and El Nino must be updated every month.
International meteorologists said that with the climate change, every thing can happen and people must be vigilant to the most severe phenomenon. The rainfall can be much in short period, or a little in long period, and temperatures can rise sharply.
Farmers should be aware that experiences passing from generation to generation can be not enough to be used in the present condition. They should keep close watch on the weather to have proper measures and limit the consequences. — VNS