The Daily Mail's different views of sea level rise
- 05 May 2011, 13:00
- Christian
The Daily Mail has produced an article covering this week's
Arctic Monitoring and Assessment Project report on Arctic melt and
sea level rise. While it gives a clear picture of the report,
it raises some questions about their coverage of the same issue
just a few months ago.
Here's the start of the piece:
The AMAS report presents itself as 'the most comprehensive
synthesis of knowledge about the Arctic that has been presented in
the last six years,' and draws on the work of over 200 scientists
who contributed to it.
It concludes that taking into account Arctic ice melt, sea
levels could rise 0.9-1.6m by 2100 (1.6m is around 5.2 feet). The
Mail article takes the top end of that range as 'the latest
doomsday prediction'.
Because the science of how ice sheets melt is not settled, it
has been difficult to provide definite estimates of how much sea
level will rise as the planet warms.
The Mail article notes this:
The most recent report from the United
Nations' Intergovernmental Panel on Climate Change (IPCC) in 2007
said the sea was likely to rise between 18 and 59cm by 2100.
However, those numbers did not include a possible speeding up of
the Arctic thaw.
Alongside their 2007 assessment of potential sea level rise,
which gave estimates of possible sea level rise under different
emissions scenarios,
the IPCC said this:
[Computer] Models used to date [to
estimate sea level rise] do not include uncertainties in
climate-carbon cycle feedback nor do they include the full effects
of changes in ice sheet flow, because a basis in published
literature is lacking. … Larger values cannot be excluded, but
understanding of these effects is too limited to assess their
likelihood or provide a best estimate or an upper bound for sea
level rise.
In other words, in 2007 the science was not sufficiently
advanced to put a firm upper limit on sea level rise. Realclimate
helpfully provided more context on this at the time
here.
What do the sceptics have to say about this? The Daily Mail
article includes a contribution from a climate sceptic
commentator:
Dr Benny Peiser, of the sceptical Global
Warming Policy Foundation, said:
"These figures seem a bit alarmist to me given that even the IPCC
has come to a different , more moderate conclusion. If you look at
what has actually been happening over last 50 years there's no
evidence of any acceleration in sea level rises. The rise has
been quite steady. Unless we see a clear signal that something
dramatic is happening to sea levels, I would be cautious."
Two points about this comment are questionable. First, there is
evidence that sea level rise is accelerating. A major gathering of
climate scientists in early 2009, for example, concluded that
The rate of sea-level rise has increased
in the period from 1993 to the present…largely
due to the growing contribution of ice loss from Greenland and
Antarctica.
Secondly, it is strange to characterise the AMAS report - new
scientific research - as 'alarmist' compared to a more 'moderate'
IPCC of four years ago, given that the IPCC noted their
figures could well be underestimates, and that it was the limited
state of the science on the issue which was preventing a clearer
picture.
Indeed, the AMAS press release notes the report will apparently
serve as the basis for the IPCC's consideration of the issue in
their next assessment report.
This piece does raise a question about how the Mail is
representing the IPCC's work. Compare and contrast with an article
from three months ago:
The two articles don't flat-out contradict one another, but it
seems odd that this week's article describes a rise of 5 feet as
'twice as high' as the IPCC's estimate for sea level rise, while in
January, the Mail described the IPCC's 'worst case' forecast for
the same date as 6ft of sea level rise.
Is this confusion a hazard of using punchy language to cover a
complicated subject? Perhaps. Using terms like 'alarmist' and
'doomsday' doesn't help to capture the fact that this is an area of
science where understanding is advancing, but not yet fixed.
However, I have been unable to find any claim by the IPCC that
6ft (or around 2m) of sea level rise by 2100 was the 'worst case'.
Rather, their message seemed to be that they couldn't put a value
on the 'worst case' because of limited scientific research in the
area - although I may have missed it.
(More recent research suggests that, based on an assessment of
glacier flow, it is highly
unlikely sea level rise would be greater than 2m by 2100.)
If you can find an IPCC source for this, please leave it in the
comments and I'll update this.