Explaining the cause of unusual heat in Asia

El Nino, along with human-caused climate change, is responsible for the unusual heat and drought that has been affecting South Asia and Southeast Asia this year.

Asphalt in New Delhi melted due to the heat. Photo: EPA

"In the Indian capital, the heat wave is expected to continue for another four days. Temperatures in Pakistan have reached 50 degrees Celsius, and heat waves are spreading from there to India," IB Times quoted BK Yadav, Director of the India Meteorological Department.

Temperatures are rising in central, northwestern, eastern and southern India, with temperatures reaching as high as 47 degrees Celsius. Temperatures are similar in the hilly regions. The scorching sun melted the asphalt on a major road in the capital New Delhi, turning the white crossings black.

The death toll from a heatwave across India has passed 1,100, with temperatures reaching more than 5 degrees Celsius above average.

The southern Indian city of Hyderabad has only five hot days a year, but in the future, the number of hot days is expected to increase to 40, according to a study on Hyderabad's climate change by the Potsdam Institute for Climate Research, Germany.

Causes and effects

Experts say El Nino is responsible for warming sea surface temperatures in the Pacific Ocean, causing hot weather across Asia. El Nino is a significant change in sea surface temperatures in the tropical Pacific Ocean, occurring every 2-7 years when the trade winds (strong winds that blow consistently from the southeast or northeast toward the equator) begin to weaken. El Nino causes temperatures to rise, causing storms, floods and dry spells.

"Over the last few hundred years, temperatures have warmed by about 0.8 degrees, and people would have suffered more heat waves even without El Nino. El Nino increases air temperatures and thus adds to global warming," said J Srinivasan, chairman of the Centre for Climate Change at the Indian Institute of Science.

A series of 22 studies, "Explaining the Extreme Events of 2013 from a Climate Perspective," clearly shows that the heat waves of 2013 were caused by human-caused climate change.

Human-caused global warming made 2014 the hottest year on record, a trend that will continue in 2015 due to an early El Nino, according to predictions from the US National Oceanic and Atmospheric Administration (NOAA).

The global average concentration of carbon dioxide (CO2) in the atmosphere exceeded the alarming level of 400 parts per million (ppm) in March 2015. The rate of increase of the average CO2 concentration in the atmosphere during the period 2012-2014 was 2.25 ppm per year. CO2 is a powerful greenhouse gas that causes global warming. The concentration of CO2 in the atmosphere is constantly increasing mainly due to human-caused burning of fossil fuels, industrial and agricultural emissions.

The world's oceans are absorbing CO2, causing the pH of seawater to change and become more acidic, causing many negative impacts on the world's aquatic resources.

The impact of El Nino on the world in 2015. Graphics: Open Snow

According to NOAA, February 2015 recorded many ocean and land areas with temperatures 0.82 degrees Celsius higher than the monthly average over the past 136 years. The average global February temperature in the 20th century was 12.1 degrees Celsius.

February 1998 also recorded temperatures 0.86 degrees Celsius higher than average. This was the year of the El Nino phenomenon, affecting 110 million people and causing nearly 100 billion USD in damage to the global economy, according to research data on the Impact of Climate Change and Indian Agriculture by Professor Prasada Rao, University of Kerala, South India.

According to VnExpress