The IPCC report: A summary for everyone
- 27 Sep 2013, 12:00
- Ros Donald
Today an international group of
hundreds of climate scientists has released a report covering
how and why the earth's climate is changing, and how it may change
in the future.
Scientists have known over two hundred years that
carbon dioxide is a greenhouse gas, meaning it traps heat in the
atmosphere and oceans.
Over time, scientists have come to understand more
about how the gases that are emitted when people burn fossil fuels
like oil and gas affect the climate.
Scientists are more sure than ever - 95 per cent
certain - that humans are causing extra warming, today's report
concludes. The oceans, land and atmosphere are getting warmer, snow
and ice is melting and sea levels are rising.
For another way of thinking about this, one news
report this week explains that
scientists are now as sure human activity is warming the climate as
they are that smoking causes lung cancer.
Oceans have a big role to play in the earth's
climate. They are the source of clouds and rain, and they have also
absorbed a very large percentage of the warming that has occurred
since the 1970s, scientists say.
Scientists are confident that this heat is causing
the huge bodies of ice in the coldest parts of the world like the
Arctic, Antarctica and Greenland to melt. It's also causing
glaciers that have formed over thousands of years in the mountains
around the world to lose ice.
The water in the oceans is warming and expanding, and
water from ice sheets and glaciers is topping it up. So sea levels
are getting higher.
This latest report says that scientists now
agree that the sea level rise that is happening in response to
warming will be higher by the end of the century than they
Climate change means we're getting more hot days and
less cold days per year, when you look at the world as a whole, the
report says. But other changes in weather will be a mixed picture
around the world.
Some places will experience more droughts and
heatwaves, while others - probably including the UK - will get more
frequent, more intense rainfall.
How much we're going to experience these effects will
depend on how much carbon dioxide we continue to release into the
atmosphere in the coming years.
If we want to limit temperature rise - and the
effects, like rising sea levels and weather disruption that flow
from it - we will have to reduce the amount of greenhouse gases we
A second IPCC report will have more detail about how
the changes the planet is seeing will impact on things like
flooding, agriculture, human society and economies.
A third, to be released early next year will examine
what we can do about it.