What is climate change?
The term "climate change" refers to changes in the world's
climate system. It includes a rise in average global
temperature, changes in rainfall, and other fundamental patterns.
The Earth's climate has always varied so the term is now more
commonly used to describe changes due to human activity.
Scientists have shown that the Earth's average surface
temperature is around 0.75ºC warmer than it was a century ago and
the 10 years up to the end of 2009 were the hottest recorded since
global surface temperature measurements began in 1860.
The Intergovernmental Panel on
Climate Change (more commonly abbreviated to IPCC) predicts a
temperature rise of between 1.1 and 6.4 ºC in the next century.
Humans and climate change
The temperature of the Earth is partly determined by what is
called the greenhouse effect. This is the phenomenon by which heat
from the sun is trapped in the atmosphere by particular gases,
including the water vapour in clouds, which creates warming effect.
If this didn't exist, the average temperature on Earth would be
around -18ºC.
Humans boost the naturally occurring greenhouse effect by
releasing extra greenhouse gases, the most significant of which are
carbon dioxide (CO2) and methane (CH4). Carbon dioxide is the main
greenhouse gas produced by human activity and is created when we
burn fossil fuels: oil, gas and coal. Carbon dioxide is also
released through land use change, such as drainage of peat bogs and
deforestation.
Naturally occurring factors, such as changes in the sun, have
also affected the earth's temperature in the past - both warming
and cooling it - but most scientists believe that these are not
powerful enough to explain the recent rapid warming.
Wider impact
The rise in temperature due to climate change causes several
knock-on effects. For example, sea levels are currently rising due
to melting ice and the fact that warmer water has a natural
tendency to expand.
Rainfall patterns have been affected too. Some areas have recorded
a rise in rainfall, some are seeing less and other areas are
experiencing the same amount falling in intense bursts. The
intensity of hurricanes has also increased and the threat posed by
the possibility of flooding caused by storm surges has
increased.
The effect on humanity
Scientists believe that the impact of climate change will range
from an increase in floods and droughts through to the displacement
of people in low-lying areas because of rising sea levels.
Agriculture and water availability will also be affected. Disease
patterns could also change as insects and parasites move to new
areas.
Many of these impacts are already being observed. One study by the
World Health Organisation (WHO) estimated that the global warming
that has occurred since the 1970s has caused more than 140,000
deaths annually by 2004.
Conservationists also point out that most plants and animals
live in a specific habitat. If that is destroyed, then some of
those animals and plants that cannot move or adapt are likely to
become extinct due to changing climatic conditions.
Runaway warming
If the climate gets too hot, the warming could become
self-reinforcing and impossible for us to stop. To have a chance of
avoiding that, experts believe we need to limit future temperature
rises to below 2ºC compared with the average temperature at the end
of the 18th century.
Many scientists believe that global average temperature increase
close to this is already inevitable due to the gases we've already
released and the fact that global emissions are still rising.
That's why they argue that it's so important to reduce emissions in
the short term.
What is the Kyoto Protocol?
The Kyoto Protocol is an international agreement, created in
1997, which set targets for industrialised countries to reduce
their greenhouse gas emissions. The targets varied between
countries, though the average was a 5 per cent reduction below 1990
levels by 2012. Most of the world's countries ratified this
agreement, including most of the industrialised nations that were
required under its terms to cut their emissions. An important
exception is the USA, which refused to implement the Protocol for
economic reasons.
Developing countries such as China and India (the former
overtook the US in 2006 to become the largest producer of carbon
dioxide in the world) were not required to commit to reducing
emissions under the Kyoto Protocol. The Protocol's first emissions
reductions commitment period expires in 2012 and negotiations
continue toward a successor treaty, but countries
remain divided on what this should seek to achieve, and whether it
should for example include reduction targets for the larger
emerging economies..
The climate conference in Copenhagen
The Copenhagen climate conference COP15 took place in Denmark in
December 2009, attended by delegations from 192 countries. Although
this meeting did not result if a new legally-binding agreement
there was a non-binding outcome in the form of the Copenhagen
Accord. It was debated and shaped by a small group of countries,
including the world's two biggest greenhouse gas polluters: China
and the USA.
The accord "recognises" the scientific case for keeping
temperature rises to no more than 2ºC but it does not contain
legally binding commitments to any emissions reductions in order to
achieve that goal. There is currently also no target for the
reduction of global emissions by 2050 - ie, no yardstick against
which to measure annual reductions. The Accord set out important
funding commitments with the richer nations agreeing to mobilize
some 100 billion dollars per year by 2020 so as to fund climate
change action, including helping the poorer countries adapt to what
are now inevitable climate changes.
Will Copenhagen make a difference?
Most greenhouse gases stay in the atmosphere for decades, so
further warming is almost inevitable.
The IPCC suggests that to have a reasonable chance of avoiding a
2ºC rise in temperature, global emissions would need to peak and
start to decline within around 15-20 years.
At present, the cuts voluntarily pledged by countries are not
enough to halt the overall global rise in emissions, never mind
halt temperature increase. So while the accord has been seen by
some as a step in the right direction, most experts believe that it
will not be effective until countries agree to legally binding
targets and set out plans on how they will meet them.
There are also calls for more transparent monitoring and
reporting systems to ensure that targets are met and to provide
funding to help developing countries grow their economies 'cleanly'
and adapt to existing problems caused by climate change.
If you would like to find out more about the Intergovernmental
Panel on Climate Change (IPCC), you can find them here.