John Ellwood (Letters, November v15, 'Carbon gas is beneficial') boasts about how he has contributed to increasing global CO2 levels by flying to and from California and claims this will help agricultural production.

If he took the time to read scientific opinion on agriculture under climate change he would discover that plant growth is not simply a matter of carbon supply, but also depends upon water and temperature, both of which will change as the CO2 levels increase and the world warms.

Probably the greatest effects on crop production will be to do with these rainfall and temperature effects, not the increased CO2.

It is sadly ironic that the state he flew from has in the past weeks experienced damaging wildfires, resulting in numerous deaths. According to published US scientific studies, wildfire incidence in the western states has increased over recent decades due to changing weather patterns, which are caused by the climate change brought about by mankind’s emissions of CO2.

He goes on to state that he is yet to see any effects on the weather from the increase in atmospheric CO2. That is perhaps because he has not painstakingly installed a network of monitoring stations, and collected and analysed their data over a long period of time.

Had he done so, he might have produced a report like that published a few weeks ago by the Met Office, in which changes in UK weather between 1961-1990 and 2008-2017 were clearly documented. The results showed that the temperatures of the hottest and coldest days had increased, warm spells were longer, there were fewer very cold days, the length of dry spells increased, and rainfall on the wettest days was higher.

No doubt letters denying climate change will continue to be published and if that is how people think, then so it must be. But I would ask deniers to pause and consider that you just might be wrong.

The evidence is increasingly against you, and although we do not understand everything there is a clear risk of major alterations in the Earth System, most of them dangerous to humanity, due to our emissions of CO2.

We really need to come together to use our collective intelligence to find ways of slowing climate change and adapting to its effects. The time for arguing about whether it is happening is surely over. Think of the children and the grandchildren.

Ed Tipping