Here
is the weather forecast for the next five years: even hotter
Long-range
forecast predicts generally upward temperature trend, possibly
interrupted by La Niña event in 2017
An
international team used tree ring records and historical documents to
reconstruct yearly temperatures going back 2,100 years and discovered
there was no period as warm as the last 30 years.
Robin McKie
Sunday 31 January
2016 00.05 GMT
Global temperatures
will continue to soar over the next 12 months as rising levels of
greenhouse gas emissions and El Niño combine to bring more
record-breaking warmth to the planet.
According to the Met
Office’s forecast for the next five years, 2016 is likely to be the
warmest since records began. Then in 2017 there will be a dip as the
effects of El Niño dissipate and there is some planet-wide cooling.
But after that, and
for the remaining three years of the decade, the world will continue
to experience even more warming. The forecast, which will be released
this week, is the first such report that the Met Office has issued
since it overhauled its near-term climate prediction system last
year.
“We cannot say
exactly how warm it will get but there is no doubt the overall upward
trend of temperatures will continue,” said Doug Smith, a Met Office
expert on long-term forecasting. “We cannot say exactly how hot
2018, 2019 or 2020 will be. That will depend on other variables. But
the general trend is going to be upwards.”
The current El Niño
– a meteorological event in which a band of warm water develops in
the Pacific Ocean around the equator – is about to peak. However,
global warming associated with the event normally lags several months
behind that peak and as a result, 2016 could be even hotter that
2015, the warmest year on record.
Some global warming
deniers have claimed that the current El Niño alone was responsible
for making last year a record one, with the effects of carbon
emissions being irrelevant. But Smith rejects these claims.
“We have had El
Niños before,” he said. “The one in 1997-98 was particularly
intense. Nevertheless, global temperatures were less then than they
were in 2015 – and that is because background heating caused by
increasing carbon dioxide levels in the atmosphere are higher today
than they were in 1997-98.”
However, the end of
the current El Niño and the possible triggering of a La Niña event
– an extensive cooling of the central and eastern tropical Pacific
Ocean – is likely to bring a temporary halt to rising global
temperatures, according to the Met Office.
As a result, 2017 is
likely to see a dip in global temperatures. “We can be pretty sure
there will be a drop that year,” added Smith.
After that,
temperatures could start to rise again over the rest of the decade.
“Whether one of these years – 2018, 2019, 2020 – overtakes 2016
in terms of temperature is very hard to predict at this stage,”
said Smith. “We are looking quite far into the future, after all.”
One reason for such
uncertainties is a lack of precise knowledge about the heating of the
oceans. “If you want to measure climate change you need to have
precise information about the total energy of the planet and most of
that is stored in the ocean,” said Smith. “Recently temperature
rises on the land slowed and people said global warming had stopped.
That was never true. The ocean heat content went up all the time.”
In a bid to improve
information about ocean warming trends, scientists have deployed
robot floats – part of the international Argo measuring system –
that record temperatures and salinity to depths of 2,000 metres. Now
a new generation of Argo devices is to be deployed and will reach
depths of 5,000 metres. “That should provide crucial data that will
help us make more accurate forecasts,” added Smith.
The release of the
Met Office study comes as another group of scientists revealed
research that shows the last 30 years were probably the warmest
Europe has experienced in more than two millennia. An international
team used tree ring records and historical documents to reconstruct
yearly temperatures going back 2,100 years and discovered there was
no period as warm as the last 30 years.
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