Climate Change, Grazing & Land Use March 2020There is now a new Climate change & land use section of my website.There is a lot of talk in conservation circles and the media on the impact of land use on climate change. However it is a complex subject and it would appear that carbon flows are not understood by most; for example the difference between carbon emissions from the use of fossil carbon and carbon emissions which are merely recycling of atmospheric carbon.When we burn fossil fuels we are adding new carbon to the atmosphere, the cause of global warming. However when animals belch methane this does not result in an increase on atmospheric carbon: they are merely recycling the carbon fixed by the plants they eat. Certainly the methane they belch is a strong greenhouse gas, but its time in the atmosphere is short compared to the main greenhouse gas, carbon dioxide.Animal husbandry, particularly intensive farming, certainly does release a new greenhouses to the atmosphere but this is through the use of fossil carbon in transport, farm machinery, fertiliser & pesticide production, and the processing of animal feed. However most of these outputs will also apply to crop growing as currently managed. The only way to reduce these carbon outputs is replacement of fossil fuels with renewable energy, with no input of fertilisers dependent on fossil fuels for their manufacture. Otherwise moving to a vegetarian diet will not make much difference to the climate! Certainly replacement of tropical rainforest to animal pasture in some parts of the world does add to the amount of carbon in the atmosphere, but this is not relevant to UK farming.In the UK before the advent of the industrial manufacture of fertilisers, animals were an essential part of crop rotation, the dunging effect of animals being essential to maintain long-term soil fertility. If animals are no longer part of the farming scene, then soil fertility can only be maintained through the continual use of industrial-manufactured fertilisers (although the use of legumes such as clover can fulfil the nitrogen deficit). Can these be produced in a carbon-neutral way? The return to more environmentally extensive farming does rely on animals.Additionally, a significant proportion of the UK’s biodiversity is grazing-dependent, such as chalk grassland, limestone grassland and lowland heath: if animals are no longer part of the agricultural scene, then this biodiversity will be lost. And does wool not have a bright future as a non-fossil fuel, non-plastic textile?Climate change mitigation & nature conservation not always on the same side!There appears also to be a strong belief amongst conservationists that conservation of habitats and climate mitigation are always on the same side, but there is no a priori reason why this should be the case! There are times when, if we want to conserve the landscapes and natural habitats of the UK, we will have to decide which is more important: climate mitigation or preventing the loss of habitats.The papers in the new Climate change & land use section of my website address these issues, and also point out that tree planting in the UK does not necessarily mitigate climate change.