A recent
paper published in the Nature Publishing Group's journal
Scientific Data has quantified the fraction of the global land surface in varying degrees of drought since 1982. Here is the
figure of interest:
There has certainly been no significant change in severe, extreme, or exceptional drought conditions since 1982, and it looks as though the percentage of land area under abnormally dry conditions or moderate drought has declined over the past 30 years.
The findings appear to conflict with previous
claims of "increasing drought under global warming in observations and models" and
that "increased heating from global warming may not cause droughts but it is expected that when droughts occur they are likely to set in quicker and be more intense."
This most recent study suggests global drought conditions are either becoming less of a concern over time, or at the very least, not changing.
(h/t to
Watts Up With That? and
Roger Pielke, Jr.)