Environmental Engineering Reference
In-Depth Information
industrial value; however, nitrous oxide also has a critical influence on climate
change since it has a relatively long atmospheric residual time.
Motorized road traffic using fossil fuels also causes pollutants responsible
for the formation of ground level
ozone
(O
3
). Human-induced
stratospheric
water vapour
(H
2
O) also influences the greenhouse effect. However, the extent
of the impact of these gases and other gases is difficult to estimate.
The contribution of different sources to the anthropogenic greenhouse
effect can be summarized as:
•
use of fossil fuels
50 per cent
•
chemical industry (CFCs, halons)
20 per cent
•
destruction of tropical rain forests
(fire clearance, rotting)
15 per cent
•
agriculture
15 per cent
These contributions vary regionally. In developing countries, the burning of rain
forests and agriculture have the highest climatic influence, while in industrial
countries, the use of fossil fuels dominates. As indicated in Figure 1.7, the energy
demand and resulting carbon dioxide emissions also vary enormously.
Per capita, the UK emits about 9 times more carbon dioxide than does
India; for Germany it is 11 times more and for the US, 20 times more. If the
people of all countries caused the same amount of anthropogenic carbon
dioxide as those in the US, global carbon dioxide emissions would increase five
times and the anthropogenic greenhouse effect would double. The per capita
CO
2
emissions of road traffic alone in Germany are twice as high as the total
per capita emissions in India. In the US the picture is even worse.
The reasons for climate change are controversial. Even today, studies are
published questioning the anthropogenic greenhouse effect. In fact, part of the
global temperature increase of 0.6°C during the past 100 years is linked to
natural fluctuations. However, the majority comes from anthropogenic
emissions. In most cases it is obvious that the authors who refute the existence
of anthropogenic climate change are associated with lobby groups that would
be disadvantaged if a radical change of energy policy were to take place.
There are several undeniable facts substantiating a creeping climate
change. In 2001, the following events were seen as indications for the
increasing greenhouse effect (IPCC, 2001):
•
Worldwide, 1998 was the warmest year since temperature measurements
began in 1861
•
The 1990s were the warmest decade since records began
•
Global snow cover and the extent of ice caps has decreased by 10 per cent
since the late 1960s
•
Non-polar glaciers are undergoing widespread retreat
•
Global mean sea level rose by 0.1-0.2 m during the 20th century
•
During the 20th century, precipitation increased by 0.5-1 per cent per
decade
