First Do No Harm

If you think the world is moving at a dangerously slow pace to address the peril of climate change, consider the extreme alternative: manipulating the earth’s environment on a global level to counteract the trend toward warming.

The latter tactic, known as geoengineering, has aroused immense interest among fans of mega-technology solutions as well as members of Congress and some foreign governments. Some proponents call it a necessary “Plan B” if more mainstream efforts to limit greenhouse gas emissions run into political or technological walls.

But delegates from more than 190 countries to the Conference of the Parties to the UN Convention on Biological Diversity in Nagoya, Japan are meeting today to consider the possibility that ill-conceived geoengineering could prove just as big a threat to the earth’s environment as global warming itself.

The delegates will consider a precautionary resolution that “no climate-related geoengineering activities take place until there is an adequate scientific basis on which to justify such activities and appropriate consideration of the associated risks.”

No laws currently restrict geoengineering, but two years ago, delegates to the same convention supported a ban on one widely discussed geoengineering option, to promote the growth of CO2-consuming plankton by fertilizing the oceans with iron.

A new study, published this month by a team of U.S. and Canadian scientists, confirms that plankton blooms vigorously when fed by iron-rich volcanic material, but absorbs far too little carbon dioxide to make any difference to the planet. A huge bloom created by an Alaskan eruption in 1997 added only about half of one percent to the ocean’s normal uptake of CO2 that year.

Other proposed geoengineering options would do nothing to curb rising levels of greenhouse gases, but would cool the Earth by reflecting more sunlight—for example, by creating shinier clouds or spewing reflective sulfur aerosols into the atmosphere.

One international research team reported in August that warming could be slowed for several decades by injecting as much sulfur dioxide into the upper atmosphere every 18 months as Mt. Pinatubo blasted out in one of history’s greatest eruptions in 1991.

But they warned that the consequences for the Earth’s ecosystem of such large-scale meddling were unknown. And as many scientists have noted, since aerosols wash out of the atmosphere, any breakdown in the injection system could lead to rapid, catastrophic warming in the future if atmospheric CO2 levels continue to rise.

Critics warn that geoengineering is tough to test at less than planetary scale, unacceptably unilateral if imposed by one country, and above all, risky and unpredictable. “The artificial manipulation of (solar) radiation could wreak havoc on the fragile balance of complex ecosystems that have taken millennia to evolve,” warns the ETC Group, an NGO actively involved in fighting geoengineering.

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