MR WALLACE (Letters, March 14) is, of course, correct when he asserts plants require CO2 in order to photosynthesise.

Before the industrial revolution the balance was retained between humans producing, and plants using.

However, what he has forgotten is that now industrialisation based on burning fossil fuels is the common policy, the plants can’t cope.

The coal, gas and oil we burn were carbon-based life forms many millions of years ago. By burning them now, we release CO2 that hasn’t existed since then. As we are not sequestering this (out of circulation as it was during its phase as oil) the CO2 level can only rise.

Even when used in photosynthesis and converted to carbon, it is re-converted to CO2 upon the decomposition or burning of the tree.

Only by storing the “C” of CO2 and letting the oxygen back into the atmosphere can we hope to prevent human induced climate change.

Joshua Taylor, Portland Street, York.