The Threat of Climate Change - Energy and Climate: How to Achieve a Successful Energy Transition - page 27

in latitude. This may prove fatal for an existing ecosystem, for example by
favouring the propagation of a parasite not previously present.
The relation between the various phenomena observed and global
climate change must be analysed with a certain degree of caution, given
the complexity and variability of meteorological phenomena. The fact
that they occur simultaneously is nevertheless the symptom of a dramatic
change. In addition to effects visible locally, we also observe profound
changes affecting the entire planet.

Positive retroaction and tipping points

The so-called 'positive retroaction' mechanisms are likely tomake climate
change even worse. Positive retroaction corresponds to higher CO 2
emissions, with anthropogenic emissions releasing greenhouse gases
trapped in the soil, the ocean, the earth and the biosphere.
Large quantities of methane trapped in the

2 could there-
fore be released due to a temperature increase. The methane is trapped
in crystals formed in the presence of water, the hydrates. Once the
temperature is high enough to cause decomposition of the hydrates,
methane is quickly released. Since methane has a relatively high GWP,
there is a considerable risk for the planet. The Siberian permafrost has
started to thaw, suggesting that this change could occur in the relatively
short term.
Maritime streams such as the Gulf Stream could be modified, with
consequences for the climate of the coastal regions. Climate change could
have also an impact upon interaction phenomena between ocean water
layers andwinds, such as those which produce El Ni ˜ o. El Ni ˜ o is a strong
maritime stream, which occurs periodically in the Pacific Ocean. It is
provoked by dominant winds, which induce an oscillating mechanism in
the atmosphere coupled with a displacement of surface ocean layers. This
oscillating mechanism results in modifications of climatic conditions and
of rain occurrence.
Disastrous effects have been observed as a consequence of El Ni ˜ o, such
as droughts and famines, forest fires and floods 3 , which illustrate the
possible consequences of such a climatic disorder.

permafrost

2 Permanently frozen ground of the Arctic regions.
3 The disastrous episode of massive forest fires which struck Indonesia in 1997 can be related to El
Ni ˜ o.