Rarely (if ever) has there been a requirement for the world to provide a unified response to a single issue. Climate change has become the world's biggest challenge.

It is important to understand the science, at least at a high level, so as to put the international and national legislative response to climate change into context. It then becomes clear that not only do preventative measures need to be undertaken to combat climate change, but adaptation measures as well.

The potential impacts of global warming and actions taken to combat climate change will of course continue to be subject to debate. However, what is clear is that some degree of climate change is inevitable because of the damage done to date by pollution, and that all sectors of the economy as well as individuals each have a role to play in the mitigation and prevention of further harm.

There are two key recent reports which have highlighted the need to take action and have pushed climate change to the top of the political agenda. The first, the Stern Report, was published in November 2006 and focuses on the economic aspects of climate change. The second, the Synthesis Report of the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report published in November 2007, brings together 3 aspects of climate change which the IPCC had already reported on earlier in the year. The Synthesis Report examines, in a scientific context, whether climate change is happening and the cause, the likely impacts of climate change and the options for dealing with the problem. The Stern report concluded that the costs of combating climate change are not only manageable but will lead to economic growth, whilst the costs of doing nothing could lead to an economic, human and economic catastrophe.

The IPCC report affirmed that climate change and global warming is “unequivocal”, that it is "very likely" (ie more than 90% certain) that this is due to human activities, in particular industrialisation and the burning of fossil fuels, and that impacts can be reduced at reasonable cost. This level of blame attributable to human activities signified a marked change from the IPCC predecessor report in 2001 which had determined that global warming was "likely" to be caused by human activities (ie more than 60% certain). The IPCC report is very influential, and has international status. It sets out the findings of over 2,000 top scientists worldwide and is therefore held in high regard by Governments. In fact, it was an earlier IPCC report which lead to the adoption of the United National Framework Convention on Climate Change in 1992 which in turn gave rise to the Kyoto Protocol.

Certainly, when one looks at the meteorological statistics they do "stack up" in favour of human activity being the root cause, as high temperature increases seem to go "hand-in-hand" with industrialisation. Since the late 1800s, the average global temperature has risen by 0.74°C, and by 0.6°C since 1990. Since 1850, when temperatures started to be recorded, 11 of the 12 warmest years on record occurred during the period 1995-2006 with 1998 being the warmest year.

If the world continues on a business as usual basis, ie nothing is done to combat climate change, then the IPPC report estimates as the best case scenario a temperature increase in the range of between 1.1-2.9°C, averaging at around 1.8°C by 2100. The worst case scenario is a temperature increase in the range of 2.4-6.4°C, averaging at around 4°C by 2100. Even using the minimum forecast, there will be an increase in temperature over the next century of double that since 1990, making it the highest increase over the last 10,000 years.

An increase of a few degrees in temperature does not sound very much, but in practice this could have catastrophic effects because it only takes a small increase in temperature to result in extinctions of plant and animal species. It is thought that with just a 2°C increase in temperature, 15-40% of the world's species could face extinction.

Although not facing extinction, the human race will be presented with increasing challenges. More extreme weather events are predicted, such as the severe storms, flooding and droughts seen in recent years. The hot summer of 2003, when it is estimated 22,000 - 35,000 people died from heat across Europe, will become the norm.

Agricultural yields will drop resulting in a disruption to the food supply chain. Diseases such as malaria will also become widespread. The average sea level rose by 10 to 20 cm during the 20th century, and this is expected to rise by a further 18 to 59 cm by 2100. Where the temperature increases by 2-3°C, the rising sea levels could threaten the homes of one in every 20 people. Where the temperature increases by 3-4°C, matters become extremely serious as around 200 million people could be permanently displaced due to rising sea levels, floods and droughts.

Some climate change is now inevitable because of past and current emissions. Even if global warming stopped now, because the climate does not respond immediately, the temperature would still increase by 0.5-1°C. The most affected will be the poorer countries living near the equator.

Although not cheerful reading, the science helps us to understand why we are "doing what we are doing" and to identify risks and market opportunities in future business planning.