Why time is running out to limit global warming

Political unwillingness is not the only obstacle obstructing serious steps towards reducing greenhouse gas emissions and consequent climate disturbance ("West breaks its promises over global warming", 7 July).

Even given the political will, the introduction of low-greenhouse-gas technology on the necessary scale is likely to take decades. This is because of the (normal) planning, finance and engineering application and construction processes. Some projects that look good on the drawing- board will not survive these hurdles. Newer concepts such as energy crops will also have prejudice to overcome.

It is vital that this timeframe is fully appreciated by the decision makers. We also have to sustain the forests that absorb carbon dioxide, otherwise the task gets even harder. Emitted greenhouse gases return steadily to the earth and oceans but some, including carbon dioxide, can take generations to do so.

Time is definitely not on our side. The later we leave it, the harder and more expensive reversing the process will get.

Tony Robson

Cheltenham, Gloucestershire