Science

atters

David Suzuki,
David Suzuki
Foundation

 

Stuck out in the cold on freezing February
mornings, Canadians can be forgiven for think-
ing: “Bring on global warming!” But new
research tells us we should be careful what we
wish for.

Wishful thinking about global warming isn’t
limited to cold Canadians. In fact, some people
have suggested that a warmer planet would be
beneficial for humanity—by allowing farmers to
plant crops in areas that are otherwise too cold,
for example, and by increasing tree growth and
creating more lumber. In theory, all that extra
plant growth would also suck up carbon from
the air, which could slow and eventually reverse
global warming—handily solving the problem
for us.

Sounds too good to be true, and it most like-
ly is.

However, it has been difficult to find out
how plants will actually respond to prolonged
increased temperatures. Experiments have been
conducted on small plots using heat lamps, but
these were very limited in scope and hardly
mimic changes that would take place on much
larger scales.

Scientists tell us we can expect more extreme
weather events like heat waves and droughts as
climate change progresses. Europe’s summer of
2003 gave scientists the opportunity to examine
what prolonged hot temperatures will mean for
plant growth across a large area. That summer,
temperatures soared across Europe, with aver-
ages exceeding the norm by six degrees Celsius.
Rainfall also decreased by 50 percent compared
to the average. It was a scorcher and 16,000
Parisians died from the heat.

Europe is fortunate to have an extensive net-
work of scientific monitoring stations, giving
scientists access to huge amounts of data. So
the European Union commissioned scientists to
mine those data to find out how the heat wave
affected plant growth and carbon dioxide levels.
The results were published in a recent edition of
the journal Nature.

Researchers from 17 countries examined
crop-yield information and satellite data, along
with carbon dioxide readings from 14 forest
sites and one grassland site. They found that
Europe lost 30 percent of its plant life over the
summer of 2003. This decrease in biomass
(weight of living matter) combined with an
increase in plant respiration (which releases car-
bon dioxide) means that, over the course of one

summer, Europe’s forests and fields released
more carbon dioxide than all its plants had
sucked up over the previous four years. Their
findings do not include the release of carbon
into the atmosphere from massive forest fires
that also raged during that summer.

The report concludes, “In Europe, more fre-
quent extreme drought events may counteract
the effects of the anticipated mean warming and
lengthening of the growing season, and erode
the health and productivity of ecosystems,
reversing (carbon) sinks to sources and con-
tributing to positive carbon-climate feedbacks.”

In other words, more droughts could actually
speed up climate change and make the problem
worse.

Of course, if temperature changes occur
slow enough, it’s possible that forests and crops
could acclimate and fare better. But those
increased temperatures could also lead to other
problems such as increased pests, diseases’ and
fires. The researchers say that more studies are
needed to find out what to expect in the future.

We still have an opportunity to choose that
future. By reducing the emissions that are caus-
ing the problem, we can slow climate change
and reduce the threat. What’s more, by becom-
ing more efficient and less wasteful, Canada can
become more economically competitive right
now. It will also boost innovation and creativity,
setting us up to be global leaders in the future.

Waiting longer to see what happens as our
climate changes is not just wishful thinking—it’s
stupid. Climate change may be many things, but
good for Canada is not likely to be one of them.

OPINION ©
Perceived benefits of warming don't pan out