Light a critical factor in limiting carbon uptake, even in the north
Most projections about climate change assume that, as temperatures rise, regions in the north high latitudes may become more suitable for the growth of vegetation, turning into cropland to feed increasing populations while also fixing more carbon dioxide (CO2) and slowing down climate change. Plants require appropriate temperature, water, and light conditions for photosynthesis and growth, so it seems logical that as temperatures increase in the northern high latitudes, plant photosynthesis, which uses CO2 to release oxygen, should also increase. At the same time, plant respiration, which uses oxygen to release CO2 and is also highly dependent on temperature, is expected to increase, too. The critical question still under debate is whether autumn warming might lead to an increase in carbon uptake, i.e., the difference between photosynthesis and respiration.