New
York Times: Surface temperatures have risen slower in the
past 15 years than in the previous 20, but that hasn't changed
the longer-term warming trend. Why warming has slowed in the
short term isn't known, but several theories have been
proposed, and they may all contribute. One theory is that much
of the heat trapped by greenhouse gases is being absorbed by
the deep oceans, possibly due to shifts in winds and currents.
Another points to a similar slowdown between the 1950s and
1970s. That period of slower warming may have been caused by an
increase in atmospheric pollution that reflected sunlight. And
in the past few decades, China and other developing countries
have massively increased air pollution. Despite the slowdown,
and whatever its cause, most of the hottest years on record
have occurred during this recent period of slower
warming.
