I am convinced that man is contributing to global warming which, unless checked, will seriously damage our environment and future prosperity.
Some people take a different view, but most scientists and the majority of the public agree that we must act.
But the intervention of Lord Stern, the Government's climate change adviser, this week was a sure-fire way to undermine public support for reducing carbon emissions.
He told the Times that "meat is ... wasteful" and "A vegetarian diet is better." He even suggested that eating meat would become as unpopular as drink-driving.
As I said in the House of Commons yesterday, Stern's comments were totally irresponsible and damaging to our livestock industry.
Yes, farming needs to play its part to reduce emissions. Worldwide, livestock contributes to 18 per cent of greenhouse gas output.
But a third of that is because rainforests are being chopped down instead of using land more efficiently. We can help developing countries protect their rainforests and modernise their agriculture.
Another third comes from manure, which can now be used to generate energy.
Most of the rest is emitted by the livestock itself. But in the last decade, improved breeds have been able to cut the harmful gases produced by the best dairy cows by a quarter.
We can also use the soil to store carbon. In fact Greenpeace says that it's possible to "mitigate close to 100 per cent" of direct agricultural emissions in ways like these.
British farms are already relatively carbon-efficient. Our livestock accounts for 7 per cent of UK greenhouse gas emissions - and just 1 per cent of total carbon emissions.
I believe in choice, and I respect people who choose to be vegetarians. But I've no intention of letting people like Lord Stern deprive me of my roast beef.
It's nonsense to suggest that we must all stop eating meat to tackle climate change. Preventing global warming is an important cause. We can't allow foolish comments to undermine it.