Environmental Engineering Reference
In-Depth Information
agricultural production. The result could be famines and mass migrations.
Furthermore, global warming will increase storm intensities with disastrous
effects in tropical regions as well as in mid-range latitudes. Global sea level
will rise between 0.1 and 0.9 metres in this century. The long-term sea-level
rise could be as high as several metres, with severe influences on low-lying
regions. Recent flood disasters give us an indication of what is to come. For
example, about 139,000 people died from floods in Bangladesh in 1991. Many
low-lying regions and islands will disappear from the map.
It is a sad fact that these consequences cannot be avoided completely. The
limiting of global warming to +2°C is possible only if enormous efforts are
undertaken immediately. By the year 2100, the various greenhouse gas levels
must be reduced drastically compared with 1990 levels. This could be achieved
in the following way:
•
decrease global carbon dioxide emissions by 70 per cent
•
reduce global N
2
O and CH
4
emissions by 50 per cent and 5 per cent,
respectively
•
completely ban the use of all CFCs, halons and HFC-22.
Furthermore, demographers predict an increase of the world population to 15
billion (IPCC, 2000) (see also Table 1.16), more than twice the current
population. Consequently, to achieve a 70 per cent reduction in global carbon
dioxide emissions, the per capita carbon dioxide emissions in 2100 will have
to be reduced to 15 per cent of the emissions for 1990.
The industrial countries cause the largest amount of emissions. The
developing countries are currently lagging behind, but if they catch up, the
industrial countries will have to achieve the following higher emission
reductions for effective climate protection:
• 25 per cent reduction of CO
2
emissions by 2005 compared with 1990
• 50 per cent reduction of CO
2
emissions by 2020 compared with 1990
•
80 per cent reduction of CO
2
emissions by 2050 compared with 1990
•
90 per cent reduction of CO
2
emissions by 2100 compared with 1990.
This would mean a virtually complete withdrawal from the use of fossil fuels
in this century. Technically and economically this is possible; however, in the
face of a half-hearted climate policy, every possible effort has to be made.
It is not impossible to adhere to these climate reduction targets while still
increasing global prosperity. However, everybody has to recognize the necessity
of strong reductions and the consequences of failure. Sufficient possibilities to
cover our energy demand without fossil energy sources exist today: the power
industry could be based entirely on renewable energies. Thus, the question of
whether
our energy supply could be managed without fossil fuels is easy to
answer. The question yet to be answered is: when will society be ready to
establish a sustainable energy supply without fossil fuels and face up to its
responsibilities to future generations?
