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October 12, 2018

Is There Hope on a World Warming at 1.5 Degrees Celsius?

by Arshad Khan


The Inter-Governmental Panel on Climate Change has concluded the finalization of a
special report on the impact of a 1.5 degree Celsius global warming above
preindustrial levels.  Meeting in Incheon, South Korea (October 1-5), its three working
groups of experts and government officials have huddled and jousted to strike a
consensus on what will be necessary to restrict warming to 1.5 degrees Celsius when
the globe is already up a degree.  What will earth be like with this level of warmth and
what will happen if we fail?

Two earlier versions (January and June 2018) of the report were depressing to
frightening.  They were made available for about a month for comment by experts and
interested parties.  The real problem is a narrow window because human activity in
the world emits 40 billion tons of CO2 per year — about 90 times the emission from
volcanoes.  At some point, there will be enough in the atmosphere where the 1.5
degree rise will be a foregone conclusion.  While guesswork to some extent, it
appears we have about 12 years before we exhaust the ‘carbon budget’; if we accept
a 2C rise the date is 2045.

The tone may have been softened in the second report, but there is ‘substantial’
certainty the 2 degrees C target of the 2015 Paris Agreement, once considered safe,
would be dangerous for humanity.  As the agreement also required governments to
pursue efforts to limit temperature rise to 1.5 degrees C, the remit to IPCC was to
prepare a report comparing the consequences of the two alternatives as well as the
feasibility and effort required to limit the rise to the lower figure.  The final report
released on Oct 8, 2018 reviews 30,000 publications.

The fact that parts of the earth are already warmer than the 2 degree C figure and
the results are observable should be a driver for governments.  In the Arctic, for
example, where temperatures have risen up to 3 degrees C, the effort has seen
chunks of icebergs breaking off and polar bears having difficulty in catching seals
because of fewer blowholes — where they normally wait in ambush.  Current
temperatures are higher than they ever have been in the past two millennia.

For low-lying Pacific Islands the 1.5C goal is critical for many there would lose habitat
and some islands are expected to disappear under the 2C target.  The Maldives in
the Indian ocean are partly under water, and some Pacific islands have already
disappeared as average world sea levels rise by 3 mm a year.  Yet Tuvalu has
become an exception and its land area, studied from 1971 to 2014, is growing.  Eight
of its nine atolls are found to be still rising, increasing the “area by 29 percent, even
though sea levels in the country rose by twice the global average.”

Even so the consequences of the earth already being 1 degree C higher than
preindustrial times are apparent in the proliferation of extreme weather events.  
Unduly powerful hurricanes as in Puerto Rico or Houston, record-breaking forest fires
in the U.S. and Australia, monsoons in South India this year that in Kerala have been
the worst in a century, and the record temperatures in northern Europe are a few
examples.  Now the 155mph Category 5 Hurricane Michael, 5mph short of Category 6,
has devastated the Florida panhandle and continued its destruction onward into
Georgia and beyond.  It may be the strongest so far to hit this part of Florida, but as
the earth’s mean temperature rises it increases both frequency and intensity.

The IPCC report presents four pathways (p.19 Executive Summary) each with net zero
CO2 emissions within the next quarter century.  The least interventionist scenario
utilizes only afforestation to remove CO2.  The report is optimistic in demonstrating
synergies (p.27) with sustainable development goals.  That CO2 removal
technologies known as direct air capture (DAC) are also being developed successfully
adds to the optimism.

At the same time the warnings are clear.  All the options require a rapid
decarbonization of the fuel supply i.e. no fossil fuels — coal just about gone by 2050
and three-quarters of the energy from renewables (p.19 after four pathways graphs).  
The risks for fisheries and coral reefs will remain high (p.13) even with the 1.5C
scenario and coastal populations and farming will be worse off than now.  Severe
weather consequences can be expected to worsen.  But all that is the world to be.  
Hence the argument for the most interventionist scenarios where the atmospheric
CO2 is eventually reduced.

For all this the need to act now is clear in the facts and numbers.

Arshad M. Khan is a former professor who has, over many years, written occasionally
for the print and often for online media outlets.