The environmental effects of climate change are numerous and difficult to predict. When climate change first came on to the political agenda in the late 1980s, there was a heated debate about its effects. However, the majority of scientists and experts - and virtually every government – now acknowledge that climate change is real and that we need to take global action to mitigate its effects.(Animation - right click to zoom, left click to zoom out]
The continued use of fossil fuels will change the global climate. More than 95% of the fuel used for transport (e.g. diesel, petrol or kerosene for aircraft) is fossil-based. When using fossil fuels, carbon materials - such as oil or coal - are removed from the earth's crust, where they have been stored for millions of years. Extraction and use of these fuels emits the carbon as carbon dioxide (CO2).
Burning of fossil fuels increases atmospheric concentrations of CO2. The concentrations of CO2 in the atmosphere have increased 70% from 29 Gt CO2eq in 1970 to 49 Gt CO2eq in 2004 – 25.8 Gt of which came from CO2 emissions from fossil fuel combustion.
Higher atmospheric CO2 concentrations reflect heat from the earth that otherwise would have dissipated into space. This has the effect of slowly heating the earth, thus changing the global climate (commonly referred to as "the greenhouse effect"). The rise in temperatures lasts for several centuries before the carbon dioxide is adsorbed into the sea.
Incomplete combustion of fuels in engines also creates solid particles, called particulate matter, which are released into the atmosphere, and has a catalytic effect on climate change. Black carbon is always a component of particulate matter emitted from combustion sources, and is the third largest contributor to the positive radiative forcing that causes climate change.
Other, transport infrastructure and operations are vulnerable to a changing climate, especially when considering changes in sea levels, temperature, precipitation, wind strength and storm frequency, and when considering variable regional effects, emission mitigation efforts may be overwhelmed by climate change adaptation measures. Improving fuel efficiency and promoting newer, more fuel efficient cars, will also reduce other vehicular emissions that contribute to global climate change, especially N2O and black carbon.
To limit global temperature rise to 2°C, effectively limiting the impact and damage of climate change, the Intergovernmental Panel of Climate Change (IPCC) recommends stabilization of CO2 concentrations at 450 ppm. In order to reach this ambitious target, the IPCC suggests that a 50% reduction of GHG emissions from present levels in all sectors by 2050 will be necessary.