Ocean surfaces record warmest temperatures

Surface warming The world’s combined average land and ocean surface temperatures were the second warmest on record for August. file photo

The world’s ocean surfaces have just had their warmest summer temperatures on record, the US national climatic data centre said.

Climate change has been steadily raising the earth’s average temperature in recent decades, but climatologists expected additional warming this year and next due to the influence of El Niño.

Ocean surface temperatures were the warmest for any August since record keeping began in 1880. For the June to August summer months, average ocean surface temperatures rose to 16.9C (62.5F), which is 1.04F above the 20th century average, said the report from the climate centre, which is a branch of the National Oceanic and Atmospheric Administration.

The world’s combined average land and ocean surface temperatures were the second warmest on record for August, and the third warmest for the summer months.
“During the season, warmer-than-average temperatures engulfed much of the planet’s surface,” the centre said. Australia and New Zealand had their warmest August since records began.

However, central Canada and the United States were the exceptions, with unusually cool temperatures. “In some areas, such as the western United States, temperatures were much cooler than average,” the report said.

Effects of El Niño
The unusually warm summer temperatures for much of the world’s oceans were due to El Niño, the periodic warming of the Pacific. If El Niño strengthens, global temperatures are likely to set new records, the report said. So far, 2009 has been the fifth warmest year on record.
Some scientists have suggested that the effects of El Niño, coupled with warming due to climate change could well make the coming decade the hottest in human history. Nasa predicted at the start of this year that 2009 and 2010 could see the setting of new global temperature records.
The report also noted the continuing retreat in Arctic sea ice over the summer. Sea ice covered an average of 6.3m sq kilometres (2.42m sq miles) during August, according to the national snow and ice data centre. That was 18.4 per cent the 1979-2000 average.
The Arabian Sea, which has warmed by 0.50 C over the past nine decades, is experiencing a shift in its climate. So much so that intense cyclones with wind speed of more than 100 km per hour have become frequent, said a team of marine scientists led by the National Institute of Oceanography (NIO), Goa.

Arabian sea and rising temperature
Scientists have analysed 37 years of cyclone data of the sea and found the frequency and intensity of cyclones during May and June have increased fivefold between 1995 and 2007, compared to the previous 25 years from 1970 to 1995. Intense cyclones are usually observed in the tropical basins of the Atlantic and Indian oceans.
Usually, when the Arabian sea heats up in the summer, the upwelling system of the sea driven by summer monsoon wind brings cooler water to replace the warmer water and offsets the rising temperature of the sea surface. But it has failed to do so beyond 1995, the scientists said in the online edition of Marine Environmental Research in June.
To understand the anomaly, the scientists analysed the CO2 emissions and CO2 concentration in the atmosphere during 1960-2006, and found a strong correlation of the sea surface temperature with the CO2 emissions and concentration after 1995. After 1995, the upwelling-driven cooling was unable to offset the CO2-induced warming of the sea, resulting in its secular warming, they said.

The change is affecting the adjacent western India, with decreased rainfall, progressively warmer winters and consequently resulting in a 16-fold decrease in wheat production after 1995, said the NIO team. Not all agree with the findings. Debashis Lohar of Jadavpur University, Kolkata, said at this rate there would have been a negative production of wheat by now.

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