ZCZC
BFF-43
CLIMATE-OCEANS-WARMING
Oceans were hottest on record in 2019
PARIS, Jan 14, 2020 (BSS/AFP) – The world’s oceans were the hottest in
recorded history in 2019, scientists said on Tuesday, as manmade emissions
warmed seas at an ever-increasing rate with potentially disastrous impacts on
Earth’s climate.
Oceans absorb more than 90 percent of excess heat created by greenhouse gas
emissions and quantifying how much they have warmed up in recent years gives
scientists an accurate read on the rate of global warming.
A team of experts from around the world looked at data compiled by China’s
Institute of Atmospheric Physics (IAP) to gain a clear picture of ocean
warmth to a depth of 2,000 metres over several decades.
They found that oceans last year were by far the hottest ever recorded and
said that the effects of ocean warming were already being felt in the form of
more extreme weather, rising sea levels and damage to marine life.
The study, published in the journal Advances in Atmospheric Sciences, said
that last year the ocean was 0.075 Celsius hotter than the historical average
between 1981-2010.
That means the world’s oceans have absorbed 228 Zetta Joules (228 billion
trillion Joules) of energy in recent decades.
“That’s a lot of zeros,” said Cheng Lijing, lead paper author and associate
professor at the International Centre for Climate and Environmental Sciences
at the IAP.
“The amount of heat we have put in the world’s oceans in the past 25 years
equals 3.6 billion Hiroshima atom bomb explosions.”
The past five years are the five hottest years for the ocean, the study
found.
As well as the mid-term warming trend, the data showed that the ocean had
absorbed 25 Zetta Joules of additional energy in 2019 compared with 2018’s
figure.
“That’s roughly equivalent to everyone on the planet running a hundred
hairdryers or a hundred microwaves continuously for the entire year,” Michael
Mann, director of Penn State’s Earth System Sciences Center, told AFP.
– Centuries of warming –
The 2015 Paris accord aims to limit global temperature rises to “well
below” 2C, and to 1.5C if at all possible.
With just 1C of warming since the pre-industrial period, Earth has
experienced a cascade of droughts, superstorms, floods and wildfires made
more likely by climate change.
The study authors said there was a clear link between climate-related
disasters — such as the bushfires that have ravaged southeastern Australia
for months — and warming oceans.
Warmer seas mean more evaporation, said Mann.
“That means more rainfall but also it means more evaporative demand by the
atmosphere,” he said.
“That in turn leads to drying of the continents, a major factor that is
behind the recent wildfires from the Amazon all the way to the Arctic, and
including California and Australia.”
Hotter oceans also expand, leading to sea level rises.
The United Nations Intergovernmental Panel on Climate Change in a landmark
oceans report last year warned that tens of millions of people could be
displaced from coastal areas by the end of the century because of encroaching
seas.
And given that the ocean has a far higher heat absorption capacity than the
atmosphere, scientists believe they will continue to warm even if humanity
manages to drag down its emissions in line with the Paris goals.
“As long as we continue to warm up the planet with carbon emissions, we
expect about 90 percent of the heating to continue to go into the oceans,”
said Mann.
“If we stop warming up the planet, heat will continue to diffuse down into
the deep ocean for centuries, until eventually stabilising.”
BSS/AFP/SSS/1813 hrs