If the discussions at this year’s meeting of the American Association for the Advance ment of Science are any indication, the only debate about human-induced global warm ing that is meaningful any more is not over whether it will occur, but over the extent of disturbances to the natural and social world that it will wreak. And if there was a second subtext, it was the enormous impact that humans have had on natural resources through over consumption and other equilibrium-altering activities.
This was all in keeping with the conference theme: “Where Science Meets Society.” And given the policy implications that so many of the reported studies have, it was only appro priate that the meeting should take place in Washington, D.C. Despite the proximity to the seat of government for the nation that has to date avoided taking the lead on such issues, few of Washington’s policy-makers were there to receive the take-home messages that the world’s leading scientists soberly delivered.
Insurance Impacts
The Bush administration may have its head in the sand when it comes to the issue of global warming, but business – specifically, the insurance business – is al ready beginning to consider the potentially catastrophic losses it could be expected to underwrite as a result of shifts in the planet’s weather.
Donald Wuebbles, head of the Depart ment of Atmospheric Sciences at the Univer sity of Illinois, organized a symposium that explored the insurance industry’s response to climate change. Climate, he said, is nothing more than “the expected weather – the mean and variability, all the statistics of weather that one expects.” He added that climate “has been changing rapidly over recent decades,” with “human activity the primary cause.”
The warmest 20 years on record have all occurred since 1980, he noted, with 1998 being the warmest year yet, followed by 2002, 2003, and 2001. Last year, 2004, will certainly be among the top ten. Melting glaciers, in creasing precipitation near the poles, and diminishing precipitation in the tropics “correspond to what the climate model says should happen as the climate warms,” he said. Other phenomena that computerized atmospheric models predict will occur as greenhouse gas concentrations increase in the atmosphere include more water vapor and cloud cover and rising sea levels – all of which have been observed in recent years, he noted.
While many of the effects of global warm ing play out slowly, what is of greatest concern to insurers are the extreme events, Wuebbles said. Higher average summer temperatures mean higher maximum tem peratures and more hot days, which can lead to damaged or failed crops, human health impacts, shifts in tourism, increased electrical demand, power outages, and busi ness interruptions, among other things. Their combined effect could be devastating for insurers, he said. Milder winters may mean fewer cold waves and associated re ductions in death and disease. But, he cau tioned, there could be drawbacks, such as extended seasons for pests or disastrous business losses in areas where winter sports are a primary economic driver.
And what affects insurance has global repercussions, noted Evan Mills, a scientist at Lawrence Berkeley National Laboratory. Insurance is the world’s largest industry, with $3 trillion a year – “that’s trillion with a T,” Mills said – in revenues; by contrast, he said, the oil industry’s revenues are about $1 trillion annually.
But insurers are poorly equipped to ad dress climate change, Mills said. “For regu latory reasons and business conventions, premiums, analysis, and pricing are based on historical experience. But if you have a regime in which the past does not predict the future, you’re in trouble.” With climate change comes increasing variability and erratic events. “It’s very hard to base actu arial experience and pricing on erratic be havior… Variability is truly increasing, and that is a worrisome thing for insurers.”
As an example of the unexpected, unpredicted variability, Mills cited the 2003 heat wave that swept across Europe. In Swit zerland, where the heat was by no means greatest, temperatures were “six standard de viations away from the Gaussian curve,” that bell-shaped line on a graph that shows normal temperature ranges. Some 35,000 people died as a direct result of the heat. Portugal saw $2 billion in wildfire losses. Nuclear plants had to shut down, causing power outages, be cause the stream water used in their cooling systems was too warm.
Other climate-change-related damages that leave the insurance industry exposed include subsidence, caused by melting per mafrost or drying soils; wind damage (a doubling of wind speed can result in a four fold increase in damage, Mills noted); wild fire losses (Mills’ own modeling showed a quadrupling of wildfire losses in California if carbon-dioxide concentrations reach twice their pre-industrial levels). Losses re sulting from sea-level rise and associated flooding and erosion are expected to be enormous. Mills cited a Heinz Center study done for the Federal Emergency Manage ment Agency in 2000 that predicted 25 percent of houses within 150 yards of the coast will be lost to erosion within the next 60 years.
Mills noted that insurers are increasingly becoming “pro-active,” intervening to lessen risk through such varied approaches as tightening building codes, lobbying for changes in policy (including policies to lower emissions of greenhouse gases), and increasing disaster preparedness. Frank Nutter, president of the Reinsurance Insti tute of America, underscored the point, urging insurers to begin “promoting the idea of risk-based premiums,” where the risk of a changing climate is folded into the equation.
Heat-Tolerant Coral?
Coral reefs have been remarkably resilient over time, notes Andrew Baker of the Center for Environmental Research and Con servation at Columbia University. They’ve rolled with the punches during past variations in their seawater environment. But the stresses that corals now face pose extraordinary chal lenges to their survival, he noted in his talk at the February AAAS meeting. Referring to the soaring rise in levels of carbon dioxide in the atmosphere and consequent global warming, Baker said, “We’re now approaching the no-analog Earth phase,” a situation correspond ing to nothing previous in the history of the planet.
Probably the best known effect of rising sea temperatures associated with global warm ing is the phenomenon known as coral bleaching. This occurs when heat-stressed corals expel the microscopic algae, or zoox anthellae, that give them their color.
“We have tended to focus on the effects of coral bleaching,” Baker said in a recent phone interview. “It’s visible, and we’ve seen high mortality. The biggest example of this oc curred during the 1997-98 El Niño. Mass tracts of coral reefs whitened and died, and it grabbed our attention. But it’s important to draw our focus back a little. Is there maybe something going on that is much more insidious, less visible, and below our hori zon?”
Many of the reefs devastated by bleaching events gradually recover, but when they do, says Baker, the make-up of the zooxanthellae changes. The types of algae that are most common before the bleaching are replaced by types more tolerant of heat.
This, Baker said, helps explain how reef-building corals have persisted through past swings in the Earth’s climate. The trade-off, however, is that the heat-tolerant algae pro mote far slower coral growth than do those that thrive in cooler water.
All other things being equal, the corals might still do well in warmer water. But, Baker reminded the audience, other major changes are occurring or expected to occur in the ocean environment. Some of the existing stresses on coral include effects of overfishing on reefs, habitat destruction, and nutrient pollution.
Finally, one of the predicted effects of global warming on ocean water is decreasing alkalinity, meaning less calcium will be avail able to corals and other calcifying organisms – an impact that Baker described as a “double whammy.”
“As concentrations of carbon dioxide in crease in the atmosphere, the concentration of carbonate ions available in sea water does the reverse. You might expect it to go up, but it doesn’t. The higher levels of carbon diox ide dissolved in sea water actually reduces the carbonate ion, which is what corals need to calcify.
“So, if corals become more heat tolerant as a result of climate change, it comes at a price. They become slower-growing in an environment that poses increased impedi ments to growth.”
Not only will corals be affected by re duced availability of the carbonate ion in seawater. “A very good and quite large body of literature suggests that as the carbonate ion concentration goes down, calcifying organisms of all types will see their calcifica tion rate and growth rates decrease quite dramatically as a result,” Baker said.
When Turtles Ruled the Seas
Few would argue that endangered species need to be saved. For many, the question is an aesthetic one, or perhaps one that is informed by the notion that new drugs or other products may someday be derived from obscure plants or deep-dwelling ocean ani mals.
Jeremy Jackson, of the Scripps Institution of Oceanography in San Diego, has another take on endangered species – specifically, endangered sea turtles. In his presentation at the AAAS meeting, Jackson noted the impor tant ecological role played by sea turtles. They “have an efficient metabolism of things no one else eats, such as sponges and jellyfish,” Jackson noted. The reduction of their num bers, owing to habitat loss, hunting, egg poaching, and their incidental death in fish ing, has been dramatic, and their loss “has had great ecological consequences.”
Jackson has attempted to reconstruct past populations of the green sea turtles in the Caribbean. After examining a range of historical accounts, sedimentary records, archaeological evidence, and other data, he concluded that “in the Caribbean, there were probably many millions of green sea turtles before human exploitation” – possi bly as many as 9.2 million adult turtles, compared with the present number of less than 500,000. Not only were the turtles more numerous, they were also larger, with a single adult weighing up to 500 pounds. The total biomass of the Caribbean turtles “was greater than that of the North Ameri can bison before its slaughter,” he said.
An important part of the turtles’ diet was turtle grass, which was “farmed” by the grazing animals. Now that the turtles’ num bers are so drastically reduced, Jackson said, the grass beds are overgrown and vegetation is decaying. According to Jackson, turtlegrass beds off the coast of Florida and the Gulf of Mexico eventually were lost to slime molds growing in the rotting grasses.
More than “charismatic megafauna,” the turtles, Jackson says, were “ecosystem engi neers.” And he believes that more is re quired of ecologists than merely saving the species from extinction.
To restore turtles to their rightful place in the ecosystem, Jackson argues for an ambitious restoration plan. But, he told Environment Hawai‘i in an email, “As far as I know there are no such plans for ecologi cally meaningful restoration. Most efforts are focused on the famous nesting beach at Tortuguero in Costa Rica -a very worth while effort but obviously not enough.”
‘Weekend Warriors’ Wreak Havoc
Want to start a fight? Among recreational fishers in Hawai‘i, all you have to do is suggest that they should be licensed. It can’t be that radical an idea; after all, the state has required licenses for any and all who set their hooks for catfish, bass, and other introduced freshwater fish.
While the idea may have little appeal, the failure of Hawai‘i to license marine recre ational fishers means that the state has no good way to estimate the quantity of fish that they are taking from the sea.
And measuring the impact of recreational fishers is a vital component in fisheries management, says Felicia Coleman of Florida State University. At the AAAS meet ing, Coleman noted that fisheries managers have generally accepted that about 2 per cent of the total catch is taken by recre ational fishers.
But that rule of thumb breaks down when closely examined, says Coleman. Off the west coast of the United States, she said, 87 percent of the total catch of overfished stocks is taken by recreational fishers. By requiring recreational fishing licenses, she said, fisheries managers would have a way of tracking overall catch that is far more reli able than shore surveys.
The idea has gained favor recently among federal fisheries managers here in Hawai‘i. Confronted with diminishing stocks of big eye tuna (and apparently large takes of juvenile bigeye), the Western Pacific Fishery Management Council voted recently to include the possibility of recreational li censing as one arrow in its quiver of ap proaches to dealing with the problem.
— Patricia Tummons
Volume 15, Number 11 May 2005