Global environmental politicsBy November 2005 the Montreal Protocol and London Amendments had 189
and 179 ratifications respectively (ibid: 3).
◗ Climate change^5
The major climate change issue concerns the ‘greenhouse effect’, a natural
phenomenon whereby various atmospheric gases keep the Earth’s tempera-
ture high enough to sustain life as we know it. These gases, which include
carbon dioxide (CO 2 ), methane, nitrous oxide and halocarbons, allow radia-
tion from the Sun to pass through but then absorb radiation reflected back
from the Earth’s surface, trapping heat in the atmosphere. Without the nat-
ural greenhouse effect it is estimated that the average global temperature
would be about 33 degrees centigrade lower. However, it seems that human
activities, notably carbon emissions from burning fossil fuels and deforesta-
tion, and methane emissions from agricultural activities such as livestock
and paddy fields, have strengthened the greenhouse effect by increasing the
concentration of these gases in the atmosphere. It is the fear that a human-
made process of global warming is taking place with a range of potentially
devastating implications for the planet that makes climate change the most
important contemporary global environmental issue.
Scientific research has focused on three key questions. Is there evidence
of global warming? If so, is it caused by human activities or is it a natu-
ralcyclical fluctuation in temperature? What is the likely impact of global
warming?There have been huge advances in the science of climate change
in recent years, co-ordinated by the work of the Intergovernmental Panel on
Climate Change (IPCC), but the direct relationship between rising temper-
atures, emission levels, higher concentrations of gases and, crucially, their
combined impact remains uncertain. Nevertheless, there is now a broad
consensus on the answers to the three questions. Climatological evidence
shows that the Earth is getting warmer; global mean surface temperature
rose by about 0.6 degrees centigrade over the last century, and is projected to
increase by between 1.4 and 5.8 degrees (relative to 1990) by 2100 (IPCC 2001 ;
see also Dessler and Parson 2006 :ch. 3). Concentrations of the key gases in
the atmosphere have increased substantially during the twentieth century.
Most scientists now agree that these gases have contributed to temperature
increases and that human activities have produced these higher concentra-
tions. If temperatures continue to rise at a similar rate, the impact of global
warming could be devastating.^6 Ariseinglobalaveragesea-level of between
9and88centimetres by 2100 (IPCC 2001 )will flood many low-lying lands,
while the disruption of global weather systems will alter patterns of land
use, reduce agricultural yields, increase water stress and create millions of
environmental refugees. Although it remains in the world of informed spec-
ulation precisely which countries and regions will suffer most, how soon and
byhow much, it is certain that less developed countries will suffer the worst