Some of the side effects of the Asian cloud will aggravate existing
problems, like the looming Third World water crisis. Aerosols block
the sunlight, causing evaporation on the ocean surface, and thus inter-
fere with natural rain patterns. “In my own work, the most worrisome
effect is on the water cycle of the planet,” Ramanathan says. “This is
the century for water shortages, and the last thing we need is this par-
ticulate effect, but we appear to be stuck with it.”
One of the reasons people have a hard time understanding global
warming is its great complexity, and there is nothing simple about the
Asian cloud. Barry Joe Huebert, an atmospheric chemist at the
University of Hawaii in Honolulu, says that by blocking the solar radi-
ation reaching the surface of the earth, aerosols can have a cooling
effect that counteracts global warming. In the month of April, he says,
the surface cooling effects of aerosols downwind of Asia are 10 percent
higher than the warming caused by the release of greenhouse gases. A
chart in the UNEP report shows cooling caused by the haze and heat-
ing caused by global warming roughly canceling themselves out. But
that hardly makes the Asian cloud benign. Huebert told National
Geographicthat increasing temperature differences could ratchet up
the intensity of storms. “One possibility is that this could cause more
severe storms, more droughts and more floods.”
Ramanathan agrees with Huebert that sometimes contradictory
forces are at work. “The Asian plume is having a cooling effect on the sur-
face,” he says, “but at the same time it is also warming the atmosphere.”
The cycle of both droughts and floods observed by Huebert is
potentially catastrophic. The loss of ocean sunlight may be dramati-
cally altering the whole hydrological cycle, a possible explanation for
the severe droughts India has been experiencing. In yet another effect,
aerosols are caught up in regional thunderstorms, falling back into the
ocean as acid rain.
“The haze affects the optical properties of the clouds, making them
brighter,” says Dr. Joseph Prospero a professor of marine and atmos-
pheric chemistry at the University of Miami and an INDOEX partici-
pant. Clouds also become more reflective and longer-lasting, a further
cooling effect. Warming comes into it, too, because the pollutants are
very dark and absorbing, taking in large amounts of sunlight. “When
88 Jim Motavalli