Are you wondering why it's so hot today?

Is it just a freak summer? Or proof of global warming? As temperatures hit record highs, what's fuelling the heatwave?

Cars

Soaring emissions of carbon dioxide (CO2), an inevitable waste product of burning coal, oil and gas, are causing the atmosphere to retain more of the sun's heat and change the climate, with potentially catastrophic results. Britain's road transport emissions grew by 8 per cent between 1990 and 2000 and without any further policy measures to combat this, scientists predict emissions in 2010 will be 15.6 per cent higher than in 1990. This means cars and lorries in five years' time will be pumping out 46.5 million tons of carbon a year compared with 40.2 million tons in 1990.

Electricity generation

Power generation accounts for the biggest single source of carbon dioxide and equivalent greenhouse gases, with 61 million tons being released into the atmosphere in Britain in 2004. This was about 40 per cent of our total greenhouse gas emissions. A switch from power generation using coal and oil to gas, nuclear energy and renewables has led to a fall in annual emissions since 1990. However, growing energy demands - and the closure of many nuclear power plants over the next decade - makes it by no means certain that this decline will continue.

Aviation

Carbon emissions from jet aircraft represent one of the fastest-growing sources of greenhouse gases. Scientists forecast that by 2030 the amount of CO2 or equivalent greenhouse gases released by UK aviation could produce 16 to 18 million tons of carbon annually; it is also thought that the effect on the climate of releasing greenhouse gases at high altitude could be between two and four times greater than releasing CO2 at ground level. Cheap air travel does not take into account the cost to the environment.