Global Warming: causes and effects

Being at the core of a burning debate, the issue of global warming is raising more and more unanswered interrogations.

While scientific studies on the subject continue to pour in, great uncertainties still linger on over the quantitative assessment of climate evolution and over the role of Man in the current global warming. The hypothesis of such a link is nonetheless gaining more and more credibility in public opinion and reinsurers are getting immensely interested in the matter.

The causes of global warming

Greenhouse gases

global warming

For the majority of climatologists, it is henceforth unquestionable that Man is playing a crucial role in climate warming. The rise of CO2 levels dejected in the atmosphere due to human activities is directly threatening polar icecaps, coral reefs survival, and even the sheer existence of low-land countries. The rate of green house effects has risen by 30% since 1750, when pre-industrial era started.

Carbon dioxide in figures

Resulting from the combustion of fossil energies, carbon dioxide (CO2) is a persistent gas whose life span in atmosphere could reach about a century.

World emissions that amounted to 5.8 billion tons in 1999 have reached 7 billion tons in 2004, out of which 1.6 billion, that is 20%, is for the USA alone. A North American produces four times as much CO2 as the world average, while a West European produces twice as much.

Forecasts for the year 2018 show that CO2 emissions are constantly increasing. The “Global Carbon Budget” annual report refers to 37.1 billion tons of CO2. China is the largest producer of carbon dioxide. It is followed by the United States, Europe and India. These countries and regions alone produce more than half of the world's CO2.

Recourse to oil and fossil energy accounts for 80% of carbonic gas - the main responsible for the increase of green-house effect. The world demand in energy should be on the rise by 11% from 2018 to 2030.

The effects of global warming

A rise in sea level

According to the Intergovernmental Group of Experts on Climate Evolution (GIEC), an organism that gathers about 4 000 scientists all over the world, the average earth surface temperature has risen by 0.6° in the course of the last hundred years.

A simulation by Max Planck Institute for Meteorology in Hamburg predicts that this rise in global temperature will be contained between 4.1° and 5.8°, while the rise of sea water levels will reach 30 cm by 2100.

A reduction in plant production

A study conducted by the French Laboratory of Climate and Environmental Sciences (CEA-CNRPS), published by Nature magazine in September 2005, points out that plants production at the European level has dwindled down by 30% in 2003, in comparison with 2002, which unexpectedly resulted in a considerable reduction in the carbon quantity that is stocked by biomass.

Because of the tremendous heat and water stress, plants make use of their defence mechanisms that slow down photosynthesis and consequently the quantity of absorbed CO2.

If climatic warming is translated by an increase in the frequency and intensity of droughts, vegetations will become less efficient at mitigating greenhouse effects.

On a planetary scale, vegetable cover makes it possible to capture between 10 to 20% of CO2 human emissions. However, this green shield risks turning into a threat with the possible transformation of ecosystems into a source of carbon.

More violent hurricanes because of global warming

Cyclone GonuCyclone Gonu 2007 in the Arabic peninsula

In articles dating back to the months of August and September 2005, imminent climatologists have established «a smoking gun», that is a clear evidence linking global warming to the upsurge in hurricanes. According to them, even if the number of cyclones is not rising, extreme events tend to get more and more violent. This conclusion relaunches the debate and in a more acute manner over the impact of climatic warming on the emergence and intensity of tropical cyclones.

For, so far, the international scientific community has not managed to reach a consensus on the issue. Some hold global warming responsible for cyclonic activities, particularly strong as of 1995. Others refer to more complex and still misunderstood atmospheric mechanisms. Some studies advocate causes to high-risk areas which are more densely populated and with greater material damages, as well as overmediatization which tends to amplify the impact.

Caution is, therefore, at the order of the day because the matter rests entirely on a hypothetical link between cyclonic hyperactivity and climate warming.

Global Warming: Insurers, stakeholders in the debate

Because they support an increasingly heavy burden of the disasters losses costs, insurers are a major stakeholder in the issue of natural hazards triggered by climatic disturbances.

The matter has been at the highlight of the G8 agenda in July 2005 in Gleneagles, Scotland, during an international conference hosted by the Association of British Insurers (ABI). The latter presented a report which, for the first time, quantifies rising costs related to extreme bad weather in relation to cases of climate warming.

In the light of a study conducted by the Intergovernmental Pool on Climate Changing (IPCC) which shows that rising temperatures tend to make climates more volatile and natural disasters more violent, Insurers concluded that a slight increase in intensity is enough for damage costs to skyrocket.

As a consequence, the average bill related to extreme bad weather will rise from 16.5 billion USD in 2004 to 27 billion USD in 2080, that is, a 64% increase.

To face the problem, companies are required to increase their financial capacities. Capital requirements will report a 90% increase for hurricanes, 80% for typhoons and 5 to 10% for storms.

As a whole, in America, Japan and Europe, an additional 78 billion USD will be needed to make up for the difference between extreme bad weather and average intensity-related losses. Consequently, an 80% rise in risk premiums is foreseen at the 2080 horizon.

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