Weather and climate

If we wait until better sources of energy are developed, we will need to deploy more geo-engineering solutions, for longer, to mitigate the worst effects of climate change

Martin Beaney (PE Online 25 August) appears to have confused weather (a dynamical system that is extremely sensitive to initial conditions, i.e. chaotic), with climate (a statistical description of local, regional or global weather). No one can forecast the temperature here, in Southern England, in early February next year (that’s weather), but we can be reasonably sure that it will be significantly colder than now, in early September, (that’s climate).

The IPCC’s climate predictions are based on a number of climate models that all show an increase in the global average temperature as the atmospheric concentration of greenhouse gases increases due to our industrial and agricultural activity. The models show that the temperature rise since the start of the industrial revolution and particularly through the 20th Century is inextricably linked to the increase in greenhouse gas concentrations, mainly CO2 from burning fossil fuels. No other variable has been found that can account for the increase in temperature.

There can be little doubt regarding the accuracy of climate models. As early as 1991, GISS used a primitive climate model to predict the effect of the Mount Pinatubo eruption; the predictions were fairly close to the climate changes that followed, although the model did overemphasise cooling.

The only alternative to using climate models is to wait and see what happens. Unfortunately, the climate has a very high inertia and it will take many years (decades to centuries) before all the effects of the present increase in CO2 concentrations are apparent. By which time, if we continue to burn fossil fuels, we will have added significantly more CO2.

Few of the effects of climate change are expected to be beneficial to our industrial civilisation. If we wait until better sources of energy are developed, we will need to deploy more geo-engineering solutions, for longer, to mitigate the worst effects of climate change. This will do far more harm to our industrial base than the additional cost of carbon credits and other fiscal measures. Properly managed, carbon credits could result in the earlier development of systems to reduce our reliance on fossil fuels.

Robin Trow, Snodland, Kent

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