A new study published in the journal Science has poured cold water on a proposed scheme to alter the planet’s climate by injecting sulfate particles into the stratosphere. The unorthodox strategy, boosted by several prominent scientists, including Nobel laureate Paul J. Crutzen, was meant to simulate the effects of a volcanic eruption: Sulfur particles released from aircraft or large balloons high in the stratosphere — like the soot and sulfur dioxide ejected by volcanoes — would scatter incoming sunlight, reducing its absorption by the planet and producing a global cooling effect.
Opponents of the scheme warned that the problems it created would far outweigh any perceived benefits: They cited records of past eruptions to show that it could result in a series of crippling large-scale droughts. The Science study, led by two researchers at the National Center for Atmospheric Research in Boulder, CO, determined that pumping sulfur particles into the atmosphere would further weaken the Earth’s fragile ozone layer by sparking a number of destructive chemical reactions. The consequence, they concluded, would be to set back the ozone layer’s slow recovery by 2 decades.
These findings will no doubt help bolster the arguments of those who have argued against the use of human technologies to tinker with the Earth’s climate — a set of proposals collectively known as “geo-engineering.” Detractors criticize the schemes as being too short-sighted and largely untested. Furthermore, they insist, it is extremely difficult, if not impossible, to verify their success; this, in addition to their unknown risks and potential downsides, should preclude any further consideration of their use
Those that do support further research object to the involvement of profit-seeking companies or outside backing — arguing that future trials should be devoid of any commercial motivation.
Proponents of geo-engineering, both academics and scientists who’ve made the leap to the private sector, counter that corporations have long been valuable allies in advancing research, particularly in medicine and engineering, and that to deny them a seat at the table — and a potential financial incentive — would be self-defeating.
One of the few schemes to have gained some traction over the past year is iron fertilization — currently championed by San Francisco, Calif., based Climos, which recently raised $3.5 million from Elon Musk and Braemar Energy Ventures, and previously by the now-defunct Foster City, Calif., startup Planktos. Climos’ funding will fuel an initial demonstration cruise that will be led by a team of independent oceanographers.
The objective of this cruise is to show that fertilizing iron-limited areas of the oceans can result in a drawdown of atmospheric carbon dioxide — and its eventual sequestration in the ocean’s depths. The strategy is relatively straightforward: Adding iron sulfate to carefully selected regions will lead to massive phytoplankton blooms, which, through photosynthesis, will take up large amounts of carbon dioxide.
Climos’ hope — and the missing piece, from a scientific standpoint — is that once the phytoplankton die, they will sink to the bottom of the ocean, carrying the excess carbon dioxide with them. If that effect were to be demonstrated empirically, Climos could begin selling carbon credits and finance other cruises.
The evidence so far is mixed: While past scientific ventures witnessed a notable drawdown of carbon dioxide following the addition of iron — accompanied by a surge in phytoplankton primary production — the effect proved to be short-lived, lasting only several weeks, at best. Once the phytoplankton blooms collapsed, the absorbed carbon dioxide was released back to the atmosphere. Yet even these experimental successes were problematic: They were often much too short to see an actual change, were done in non-ideal locations and were too small in scope.
Anthony Michaels, a professor at USC who has now made the leap to the private sector, told me that, with a few important modifications, such demonstrations could yield some positive results. An advocate of iron fertilization, he believes it is worth giving it another shot; as he explains, the potential downsides of a contained trial would be limited. The upside, however, could be high.
Besides, if the demonstration were to fail, he joked, funding for iron fertilization experiments would quickly dry up. Private investors would start looking for the next big thing, and the whole concept of iron fertilization as a climate mitigation strategy would die a quiet death. He is quick to add that although he doesn’t oppose the concept of commercial-backed iron fertilization on principle, he believes a scientific expedition should first determine its validity.
Although committed environmentalists will always oppose such schemes on the ground that they involve altering the planet’s natural processes, to say that we haven’t already done so — either by spewing massive quantities of greenhouse gases into the atmosphere or by razing many of its ecosystems to the ground — is misguided at best.
The alternative is to think of what could ensue if we don’t take immediate action to start curbing emissions growth; even taking into account some of the more ambitious proposals made by Japan and several European countries, emissions, fueled by the booming Chinese and Indian economies, will continue their dramatic trend upward for the foreseeable future.
Another recently published study, conducted by researchers at the University of Colorado, Boulder, found that a complete recovery by the Antarctic ozone hole would actually intensify the impact of global warming in the Southern Hemisphere. If it continues to heal, temperatures above the Antarctic could jump by as much as 9°C by century’s end and contribute to rising temperatures worldwide. Given all the uncertainties that still surround global warming, shouldn’t we at least give iron fertilization a try?