COP21:
Climate change means that temperate Europe faces the twin threat of
life-threatening heatwaves and periods of bitter cold over the next 20 years.
By
Tim Radford
[PARIS,
6 December, 2015] – New research warns that longer, hotter and more frequent
heatwaves than those that killed 55,000 Russians in 2010, or 72,000 in France,
Portugal, Italy, the Netherlands, Germany and the UK in 2003, will hit Europe
in the next two decades.
But,
over the same period, Europe could also begin to get colder as a consequence of
a drop in solar activity, and a century-long chill could be on the way,
according to a study of long-period climate cycles.
And
if global warming accelerates, and average global ocean temperatures rise by
6°C or more, most of the living, breathing world could in any case begin to
suffocate, according to ominous calculations by a mathematician. At some point,
the providers of oxygen could begin to perish.
All
three uncomfortable projections were published as 30,000 delegates,
politicians, observers, pressure groups, and journalists gathered in Paris for
COP21, the UN summit on climate change, which is meeting to try to forge an
agreement that could, ultimately, limit global warming to a planetary average
of 2°C or less.
Magnitude index
Simone
Russo, a geophysicist, and colleagues from the European Union Joint Research
Centre at Ispra in Italy report in Environmental Research Letters that they
developed a heatwave magnitude index to cope with a problem once considered
improbable for temperate Europe − extremes of heat.
The
index is a tool for statistical analysis, and provides a way of matching bygone
events with possible future extremes. Deaths in Europe accounted for 90% of
global mortality from heat extremes in the last 20 years. And there could be
more on the way.
“Even
if global mean temperatures don’t increase too much, we’ll see more extreme
events,” Dr Russo says. “These will be hotter, longer and more frequent.”
Scientists
from universities in Northumbria, Hull and Bradford in the UK, and from
Lomonosov State University in Moscow, are not so sure. Their study in
Scientific Reports journal examines the rhythms of the sun, and foresees a
possible minimum in solar magnetic activity, which has in the past been linked
to extended cold periods in the Earth’s climate history.
The
latest research tries to reconstruct climate from 1200 AD and make a forecast
until the year 3200, based ultimately on the count of sunspots. And the
scientists think a new low is about to begin.
“Studies
have shown that, over the last 400,000 years, there were five global warming
and four ice ages,” says Elena Popova, a physicist at Lomonosov Moscow State
University. “What caused them? How much can solar activity affect the weather
and climate change?
This question is still not solved and is an extremely relevant and interesting challenge for the various researchers around the world.”
This question is still not solved and is an extremely relevant and interesting challenge for the various researchers around the world.”
Not
everyone sees a clear link between sunspot numbers and periodic swings in
global temperature. But there isn’t much argument about the importance of
plants in the generation of the oxygen for the rest of creation − and an
estimated two-thirds of this comes from phytoplankton in the oceans, which
cover 70% of the globe.
Ocean productivity
“The
rate of oxygen production depends on water temperature and hence can be affected
by the global warming,”, say Sergei Petrovskii, professor of applied
mathematics, and colleagues at the University of Leicester, UK, in the Bulletin
of Mathematical Biology.
The
scientists made a mathematical model of the processes that control ocean
productivity, and then added higher levels of warming. Were ocean temperatures
to rise by an average of 6°C by 2100, the increase would start to disrupt the
process of photosynthesis.
Right
now, this is a less than likely outcome: 184 of the 190 nations now engaged in
the COP21 summit have submitted pledges to reduce the carbon dioxide emissions
that generate greenhouse gases and drive global warming, and the latest
forecast is that, were all these pledges honoured, global warming could perhaps
be contained to within 3°C.
If
these were improved upon – and that, too, is the ambition behind the climate
summit – then the warming could be limited to 2°C. But the predictions of the
Leicester team are a reminder of the high price of failure.
They
warn: “Our results indicate that the depletion of atmospheric oxygen on a
global scale (which, if it happens, obviously can kill most of the life on
Earth) is another possible catastrophic consequence of global warming, a global
ecological disaster that has been overlooked.”
– Climate News Network
