Current data shows biosphere carbon uptake holding steady

One of the biggest questions for ecosystem scientists is the degree to which terrestrial and marine ecosystems  can continue to sequester carbon in the face of continuing human emissions of CO2 and accompanying global climate change.

This is one of the best (i.e. easiest to interpret) graphs to show that the fraction of emitted CO2 remaining in the atmosphere (i.e. not sequestered) has held steady at around 50% for the last 40+ years (purple line, "Airborne Fraction").  Data Sources: Fossil fuel CO2 emissions - Land use CO2 emissions -  Airborne CO2 levels Graph by Willis Eschenbach.

Similar conclusions were reached by the National Oceanic and Atmospheric Administration’s Earth System Research Laboratory in Boulder, Colorado last year.

Desertification

Land-atmosphere feedbacks amplifying climate change in the Sahel. Click on image for a zoom.
From Dryland Systems in Ecosystems and Human Well-Being: Current State and Trends, part of the Millennium Assessment.


Service of Climate Regulation in Drylands. The central grey box --the components of biodiversity involved in service provision-- maintenance of soil moisture (bottom left) and modulation of rainfall (top). IN bold -- the major alternative/complementary function involved in the effect of live vegetation cover on rainfall: successive multiplication of signs along each trajectory generates an increase in rainfall (+) when service is ameliorated and a decrease in rainfall (-) when land is degraded. Land degradation (grey circle) degrade the service through affecting surface temperature; when surface temperatures increase along the albedo trajectory, it decreases along the evaporation trajectory; this trend is reversed when land is not degraded.

Much more information on desertification in Africa.