Changes in land use are sometimes blamed in discussions about human-induced global warming, along with the more usually stressed burning of fossil fuels. In a related context, it is now thought that the heaths and moorlands of the UK might prove themselves as a key instrument for removing CO2 from the atmosphere, thus scoring on the "black" side of the balance sheet for carbon emissions. However, researchers in the Stockholm Institute at York University have warned that the moorlands are a timebomb for climate change, because the combination of a warmer climate and poor land management are causing them to dry out, hence releasing "carbon" (as CO2 and methane). It is reckoned that 13 million tonnes of "carbon" is released each year from soil across the UK., which is around one tenth that produced by the nation's industries, and that better land management could limit these emissions by 400,000 tonnes of carbon per year, which is the equivalent of removing 2% of the UK's cars from the roads.
Dr Andreas Heinemeyer said: "The heather moorlands are a potential timebomb as far as carbon emissions are concerned. Global warming appears to be accelerating the release of carbon from the soil into the atmosphere. The amount of carbon in the peat soil means that this could have a catastrophic effect on global warming. It could lead to a vicious circle with global warming causing more carbon emissions, which in turn cause climate change."
The significance of this work is that is provides a microcosm of the world situation. There are billions of tonnes of "carbon" locked-up in permafrost, e.g. in Siberia, and it appears that the warming climate is causing the decomposition of the methane-hydrates they contain, thus releasing methane into the atmosphere. The actual radiative forcing factor for methane is around 100x that for CO2, meaning that one tonne of methane has a heating effect of about 275 tonnes of CO2 (allowing for the larger molecular mass of CO2 - 44 compared to 16 for methane). Nearly half of the human CO2 emissions can also be blamed on changes in land use - poor soil management (using chemical fertilisers without replacing the organic component, which leads to a steady loss of carbon from the soil), cutting down and burning forests etc.
The main cause of CO2 increasing in the atmosphere, however , is burning fossil fuels, and much of that for transportation. Although there remains speculation over the precise role this may have in forcing climate change, the obvious way around the phenomenon per se is to burn less oil as a fuel. As the world's oil supply runs out, that contribution will necessarily fall; however, we will then be left with trying to find alternatives to keep the world running, albeit according to a completely different format, based on localisation not globalisation.
It would be an obvious circumvention of both CO2 emissions and squandering preciously limited oil supplies to find some alternatives to the status quo as immediately as is practicable. I am heartened that in principle at least, large quantities of "oil" might be grown in the form of algae, which seems to address the central issue here - leaving petroleum "oil" alone and also withdrawing CO2 from the atmosphere, acting as a kind of carbon "holding tank". If CO2 is indeed the culprit for the warming Earth, then this action will help to reduce the warming and drying of the wetlands. Energy to drive farm machinery and a terrestrial carbon source (algal fertiliser, if you like) might also be provided for the rejuvenation of the carbon content of soils which will aid both their role as carbon sinks and an improved crop yield (in general) from these better soils. We may begin to find a symbiotic solution to many of our problems which we have the tendency to perceive in reductionist isolation. Nature does not work in this way, and the necessary holistic approaches may be at hand.