|
Vol. XXXVII
No. 40 October 06, |
IPCC 5th Assessment Report:
Climate Change Raging On
Raghu
THE season for
the volume by volume
publication of the much-awaited Fifth Assessment Report
(AR5) of the
Intergovernmental Panel on Climate Change (IPCC) opened
last week with the
releases on 27 September 2013 of the Summary for Policy
Makers (SPM) of the
Working Group I (WG1) Report, and the release on 30
September 2013 of the
unedited version of the Report itself.
AR5/WG-I deals
with the Physical
Science Basis i.e. dealing with the current and updated
scientific
understanding of the status and prognosis of climate
change. The coming months
will see a steady stream of similar releases, of the
Reports of Working Group
II on Impacts, Adaptation and Vulnerability and Working
Group III on Mitigation
strategies, and finally a Synthesis Report scheduled for
October 2014. The
release of the WG-I Report and its SPM have been timed, as
has been the
practice earlier too, to provide valuable inputs into the
next Summit of the UN
Framework Convention on Climate Change (UNFCCC) due to be
held in Warsaw,
Poland in November 2013.
As expected by
most scientists and
others around the world closely following climate science,
AR5/WG1/SPM clearly
shows that the scientific evidence for a deep-rooted and
worsening climate
crisis is now stronger than ever before, demanding urgent
and robust action
globally. What these measures should be, and what the
respective
responsibilities of developed and developing countries
should be, will be
covered only in the WG-III Report likely to come out in
mid-2014. But the
strong evidence-based urgency underlined by AR5/WG1 leaves
little doubt that,
prior to the UNFCCC Paris Summit in end-2015 which is the
new deadline for
reaching a global climate deal, IPCC representing the
world scientific
community will issue the hitherto strongest call for
stringent action to
contain the climate crisis.
Since the IPCCs
Assessment reports
are issued only once in 6 years after careful study,
rigorous review and wide
consultations including with the governments of all 195
countries that are
signatory to the UNFCCC, AR5 has been eagerly awaited.
MOTIVATED
MEDIA COMMENTARY
Predictably
though, the release of
AR5/WG1 was preceded by a flurry of negative media
coverage aimed at doubting
the science, calling into question the very reality of
climate change, and
raising doubts as to whether governments and the people
should be concerned or
take serious action.
An earlier
version of AR5/WG1/SPM was
leaked over the internet about a month before the release,
followed by a
cacophony of what can only be described as motivated media
commentary
essentially misrepresenting the IPCC findings, and
dripping with scepticism and
climate denial. This tendency has now become highly
predictable. A similar
chorus of sceptical and misleading media comments appeared
before the
Copenhagen Summit too, again seeking to hijack the message
about climate change
and misdirect public attention away from the urgent tasks
required to tackle
the crisis. This time around too, the usual suspects were
at it again.
The right-wing
Heritage Foundation
and the now long-running campaign by the equally rightist
and libertarian The
Liberty Institute, both think-tanks not only questioning
science but also
railing against what they perceive as a conspiracy by big
government at an
international level no less, that would stand in the way
of business-as-usual
by global capitalism. They were joined by the infamous
so-called
Non-governmental international panel on climate change
and by climate-sceptic
media outlets such as Fox News, the Wall
Street Journal the and the New York
Times in the US, and the Daily Mail in
the UK in the English-language press. Regrettably,
highly-regarded The
Hindu too carried front-page and
op-ed stories highlighting the leaked IPCC report and
similarly misinterpreting
the key findings of AR5.
Interestingly,
almost as if acting in
concert, all these commentaries shared a common narrative,
propagated similar
climate-sceptic myths and echoed the same
misinterpretation namely that the
IPCC Report itself had revised its earlier scientific
findings and was not
concluding that global warming had slowed down,
temperature rise this century
would be less than earlier projected, and impact of
atmospheric carbon-dioxide
concentrations on global temperature would be less than
feared. It would be
comical if it were not so dangerous, that all the climate
sceptics want to use
the mis-interpreted findings of the IPCC to undermine the
credibility of the
scientific body itself and indeed to question the very
science of climate
change.
As this article
will show,
IPCC/AR5/WG1 has not only shown the opposite of what the
climate-sceptics were
claiming in that it has essentially projected an
intensification of climate
change and the factors underlying it, but has also
demonstrated more rigour,
greater sophistication and substantial advances in the
scientific understanding
of climate change.
MOUNTING EVIDENCE,
DEEPENING CRISIS
In fact, all the
evidence advanced in
AR5/WG1 is in direct opposition to all the supposed
contra-indications the
sceptics had misinterpreted. The slow-down in the warming
rate at the surface
observed during the past decade or so has been noted as
only a short-term
phenomenon not contrary to the clear long-term warming
trend, and explained at
length as being due to greater transfer of heat to the
deep oceans. As
underscored by Michel Jarraud, Director-General of the
World Meteorological
Organisation (co-founder of the IPCC along with the UN
Environment Programme),
at the press conference to release AR5/WG1/SPM, even this
temporary, short-term
slow-down does not take away from the fact the 2001-2010
decade has been the
warmest ever, and each of the last three decades have been
the warmest since
1950.
AR5/WG1 states
clearly that warming
is unequivocal and many of the observed changes are
unprecedented over decades
to millennia. All the major indicators point definitively
to exceptional
climate change: the atmosphere and ocean have warmed, the
amounts of snow and
ice have diminished, sea level has risen, and the
concentrations of greenhouse
gases have increased. The atmospheric concentrations of
carbon dioxide,
methane and nitrous oxides have increased to levels
unprecedented at least in
the last 800,000 years as evidenced by analysis of carbon
datable Arctic ice
cores which store trapped air from hundreds of thousands
of years ago. CO2
concentrations have increased by 40 per cent since
pre-industrial times,
primarily from fossil fuel emissions and secondarily from
net land use change
emissions. In
view of all this
evidence, the Report revises upward to extremely likely
or 95 per cent the
degree of certainty of human-induced climate change, up
from very likely or
90 per cent in AR4 of 2007, and likely or 70 per cent in
AR3 in 2001.
AR5 makes the
interesting, and
significant, point that perhaps everyone has been focusing
too much on rise of
surface temperatures as the major indicator of climate
change as both evidence
and symptom, whereas warming of the oceans and sea-level
rise may be better
indicators. AR5 reveals that while surface temperatures
may see temperature
rise at different rates during different periods due to
complex climatic
factors, average ocean temperatures and sea levels have
been rising
continually. AR5 emphasises that Ocean warming dominates
the increase in
energy stored in the climate system, accounting for more
than 90 per cent of
the energy accumulated between 1971 and 2010 (high confidence), with most warming being
noticeable in the upper
ocean, that is up to depths of 700 metres.
For further
evidence, AR5 records
that the Greenland and Arctic ice sheets have been losing
mass, glaciers have
continued to shrink almost worldwide, and Arctic sea ice
and Northern
Hemisphere spring snow cover have continued to decrease
over the past two
decades. Along with expansion of ocean waters due to
warming, these have
contributed to global mean sea level having risen by 0.19
metres during
1901-2010. AR5 states with high confidence that the rate
of sea level rise
since the mid-19th century has been larger than the mean
rate during the last
two millennia!
POOR
PROGNOSIS
In terms of
prognosis, the Report has
put forward 4 scenarios or Representative Concentration
Pathways (RCP) based on
a somewhat different methodology adopted in AR5, namely
estimating impact of
atmospheric CO2 concentrations on the climate
system. In all 4
scenarios, temperature rise by the end of this century
will exceed 1.5 degrees
C. This was another point latched on to by the sceptics
who claimed that this
meant that IPCC had downgraded the threat to below 2
degrees C, the threshold
set by successive UNFCCC summits.
Thomas Stocker,
Co-Chair of WG-I,
clarified at the AR5 release press conference that this
only meant that even
the lowest scenario saw temperature rise of at least 1.5
degrees C above 1900
levels likely to be reached by 2030-35, and that, if this
scenario was to be
achieved, then extremely drastic emission cuts would be
necessary. More
realistically, the other 3 scenarios predicted temperature
rise of mean value
1.8 degrees C, 2.3 degrees or 3.7 degrees respectively
higher than 1986-2005
levels (to which one can add a further 0.7 degrees to
compare with 1900
levels). These estimates that, far from being lower than
earlier predicted,
show definitive and high temperature rises under virtually
all realistic
scenarios, considerably above the 2 degree threshold set
by UNFCCC.
The big
prognosis relates to how much
more emissions the atmosphere can hold if the 2 degree
limit is to be
maintained. AR5 has dealt with this in quite a different
manner compared to
earlier Assessment Reports in terms of cumulative
emissions and a total as well
as remaining carbon budget rather than in terms of annual
flows of GHG emissions
as in the past, suggesting that WG-III dealing with
mitigation strategies is
also likely to deal with the issue in these terms.(Regular
readers of these
columns would recall that some researchers in India,
notably the on-going
collaboration in India between Delhi Science Forum and the
Tata Institute of
Social Sciences, have been advocating this methodology for
several years,
following the growing body of scientific opinion along
these lines).
AR5 states that
the atmosphere can
hold an upper limit of around 880 billion tonnes of Carbon
if temperature rise
has to be contained within 2 degrees C. Of this, about 531
billion tonnes have
already been emitted till 2011, leaving only about 350
tonnes of Carbon from
future emissions that the atmosphere can hold. AR5 also
states categorically
that temperature rise and cumulative emissions have a
linear correlation, that
is, they rise more or less in the same proportion.
This should send
a clear and
unambiguous signal to negotiators in the UNFCCC. Whatever
targets are set for
individual countries should add up cumulatively to only
around 350 tonnes of
Carbon till 2100. Nations of the world have a couple of
years to arrive at an
equitable formula for sharing these cumulative emissions
between them, allowing
for the historical emissions by each and in proportion to
their
populations.
IPCCs AR5/WG1
on the Science Basis
for Climate Change is in many ways a remarkable document,
not just for the
major conclusions it has presented as per data available
at present, but even
more so for its showcasing of the scientific method as
well as the robust,
careful, progressively better and increasingly
sophisticated character of its
findings. There has indeed been an amazing consistency in
the scientific
findings since the First Assessment Report in 1990 which
fed into and shaped
the UN Framework Convention. The evidence has got stronger
with each Assessment
Report since then, aided by consistent improvements in
understanding,
measurement and modelling. For all those campaigning to
reverse the climate
crisis, it is important to grasp, respect, embrace and
communicate the
scientific process that has enabled humankind to
comprehend climate change, the
developmental path that has resulted in it, and the steps
that must be taken to
reverse it.
Question is, is
anyone
listening?
