Stop misleading climate claims

11.2.2009   (Met Office)

Dr Vicky Pope, Met Office Head of Climate Change, calls on scientists and the
media to ‘rein in’ some of their assertions about climate change.

She says: "News headlines vie for attention and it is easy for scientists to
grab this attention by linking climate change to the latest extreme weather event
or apocalyptic prediction. But in doing so, the public perception of climate change
can be distorted. The reality is that extreme events arise when natural variations
in the weather and climate combine with long-term climate change. This message
is more difficult to get heard. Scientists and journalists need to find ways to
help to make this clear without the wider audience switching off.

"Recent headlines have proclaimed that Arctic summer sea ice has decreased so
much in the past few years that it has reached a tipping point and will disappear
very quickly. The truth is that there is little evidence to support this. Indeed,
the record-breaking losses in the past couple of years could easily be due to
natural fluctuations in the weather, with summer sea ice increasing again over
the next few years. This diverts attention from the real, longer-term issues.
For example, recent results from the Met Office do show that there is a detectable
human impact in the long-term decline in sea ice over the past 30 years, and all
the evidence points to a complete loss of summer sea ice much later this century.

"This is just one example where scientific evidence has been selectively chosen
to support a cause. In the 1990s, global temperatures increased more quickly than
in earlier decades, leading to claims that global warming had accelerated. In
the past 10 years the temperature rise has slowed, leading to opposing claims.
Again, neither claim is true, since natural variations always occur on this timescale.
For example,
1998 was a record-breaking warm year as long-term man-made warming combined with a naturally occurring strong El
Niño. In contrast, 2008 was slightly cooler than previous years partly because
of a La Niña. Despite this, it was still the 10th warmest on record.

"The most recent example of this sequence of claim and counter-claim focused
on the Greenland ice sheet. The melting of ice around south-east Greenland accelerated
in the early part of this decade, leading to reports that scientists had underestimated
the speed of warming in this region. Recent measurements,
reported in Science magazine last week, show that the speed-up has stopped across the region. This has been picked
up on the climate sceptics’ websites. Again, natural variability has been ignored
in order to support a particular point of view, with climate change advocates
leaping on the acceleration to further their cause and the climate change sceptics
now using the slowing down to their own benefit. Neither group is right and all
that is achieved is greater confusion among the public. What is true is that there
will always be natural variability in the amount of ice around Greenland and that
as our climate continues to warm, the long-term reduction in the ice sheet is

"For climate scientists, having to continually rein in extraordinary claims that
the latest extreme is all due to climate change is, at best, hugely frustrating
and, at worst, enormously distracting. Overplaying natural variations in the weather
as climate change is just as much a distortion of the science as underplaying
them to claim that climate change has stopped or is not happening. Both undermine
the basic facts that the implications of climate change are profound and will
be severe if greenhouse gas emissions are not cut drastically and swiftly over
the coming decades.

"When climate scientists like me explain to people what we do for a living we
are increasingly asked whether we "believe in climate change". Quite simply it
is not a matter of belief. Our concerns about climate change arise from the scientific
evidence that humanity’s activities are leading to changes in our climate. The
scientific evidence is overwhelming."