‘Spate of hurricanes reminder of urgent action on climate change’
Finding : Scientists say there are links between climate change and extreme weather- UN chief - this year’s Atlantic hurricane season “will be the new normal of a warming world.”
The new normal :
Hurricane Irma in Barbuda - Category 5 storm for 3 days - the longest on satellite record”, and its winds - 300 kmph for 37 hour - the longest on record at that intensity.”
Hurricanes Harvey and Irma - first time two Category 4 storms and land fall
Hurricane Maria - Category 5 storm in Dominica and devastating Puerto Rico.
Indications for extreme weather changes:
A warmer climate -turbocharges the intensity of hurricanes.
The melting of glaciers, and the thermal expansion of the seas, means bigger storm surges
Result of extreme weather : More damages to coastal area
Major climatic changes :
Sea levels have risen more than 10 inches since 1870 and over the last 30 years
The number of annual weather-related disasters has nearly tripled
FACTS FOR PRELIMS
UN Chief : Secretary-General Antonio Guterres
World Bank and Antigua government have conducted a post-disaster needs assessment for Barbuda
Eastern Caribbean islands hardest hit by recent hurricanes are Dominica, Barbuda, Turks andCaicos, the British Virgin Islands and Anguilla,
RELATED NEWS EVENT : Here’s how lava-spewing mountains affect climate - Volcanic eruptions can trigger El Nino events, according to study
WHAT HAPPENS > Large volcanic eruptions in the tropics can lead to El Nino events, notorious warming periods in the Pacific Ocean with dramatic global impact on the climate- a new study.
HOW > Published in journal Nature Communications .
STAGE 1 : Enormous eruptions trigger pump millions of tonnes of sulfur dioxide into the stratosphere
STAGE 2 : Which form a sulfuric acid cloud
STAGE 3:This reflect solar radiation and reduce the average global surface temperature
Method to study after effects of eruption : How much sulfur dioxide goes into the stratosphere — and you can measure it with satellites the day after an eruption
PAST EXPERIENCE : El Nino peak during the year after large volcanic eruptions at Mount Pinatubo in the Philippines in 1991.
Five big eruptions — Santa Maria (Guatemala) in October 1902, Mount Agung (Indonesia) in March 1963, El Chichon (Mexico) in April 1982 and Pinatubo in June 1991.
THE MAJOR ONE : The study focussed on the Mount Pinatubo eruption because it is the largest and best-documented tropical one in the modern technology period. It ejected about 20 million tonnes of sulfur dioxide.
Findings : Pinatubo-like eruptions tend to shorten La Ninas, lengthen El Ninos, and lead to unusual warming during neutral periods.
FACTS FOR PRELIMS :
THE ENSO : The El Nino Southern Oscillation (ENSO) is Nature’s leading mode of periodic climate variability. It features sea surface temperature anomalies in the central and eastern Pacific.
THE El Nino Cycle : ENSO events (consisting of El Nino or La Nina, a cooling period) unfold every three to seven years and usually peak at the end of the calendar year, causing worldwide impact on the climate by altering atmospheric circulation
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