I asked   Mark Kane whether that morning’s USA Today was correct in blaming “El Meano,” as  the reporter had dubbed it, for the ten inches of snow that had just hit  Colorado—  a record blizzard for that time of year..  “An early storm— a lot of precipitation ahead of schedule. The suggestion is yes.” 

     On the other hand, El Nino had  blown the top off the rest of the hurricane season in the Carribean. So maybe a really strong El Nino isn’t so bad, I suggested. “Depends where you live,” Kane said. “If you live on the East Coast you’re probably not going to be so upset about it. But even here, the lack of nor’easters the last few years personally seems out of the ordinary. My impression is that it’s warming and people are still saying no.

       “The nineties have this queer cluster—  ” he continued, “five consecutive El Ninos in a row. There is nothing like it in this century except for the l911-14 cluster, then there was a doozer in 1879 which brought India the worst famine in its history. But the monsoon is normal this year.” He pulled out a computer-generated map of the Pacific.

       “El Nino is an interaction  between the ocean and the atmosphere, a cycle. What causes El Nino is the last El Nino, or its cold phase, La Nina. When it’s warm in the eastern Pacific it’s because the layer of warm water on the surface, the thermohaline, is deeper than usual. It deepens to around three hundred feet, the length of a football field. Usually the cold, deeper water is within ten-twelve meters. This has a powerful influence on marine biology. Most of the ocean is desert. You push the phytoplankton-rich water down, the anchovetas are in trouble. So are the  seals and guano birds.” His characterization of the event jived more or less with Norse’s..

       What causes this thickening of the thermohaline ? “When it is thicker in the eastern Pacific it’s thinner in west. It’s like water sloshing back and forth a box. But when it warms up in the east the cold-warm temperature contrast diminishes and the trade winds weaken.  The equatorial trade wind system collapses and you get.becalming at the ‘horse latitudes,’ as 17th-century Spanish navigators called them because  their horses on deck would die of  thirst and have to be thrown overboard. The causalities are not established. There is a theory about the size of the Eurasian snowmass, but the most solid thinking is that the tropical Pacific is the prime mover. Causality is a problem. When you’ve got a crooked roulette wheel and bet on a certain number, it comes up more often than it should, and now we’re getting mostly El Ninos. It works like that when you tilt the odds   in the mid latitudes.

       “In California,” he continued, “there are two extremes : the jet stream splits and part of what usually avoids the coast comes slamming in. But sometimes it just misses. The historical record of what El Nino does in that part of the world only goes back to 1882. This year we are supposed to be facing the most horrendous event of all time  except for  one in the twelfth century that wiped out the Moqui civilization in Peru. You can see the seawater marks on their temples. But what I don’t understand is when you warm up the planet, the El Ninos should become weaker. There is no good case for them to become more frequent and severe.”

     He hastened to add, as he rushed off to teach a class at Columbia, that “as a scientist I give you the properly qualified assessment of where we stand because we hold ourselves to a very high standard of certainty. But we don’t want to wait until we’re 98% certain. What’s the best guess (not the way science is usually couched)? I think global warming is inevitable. There is evidence that there are more extreme events. These are these things we don’t understand terribly well. The models are still crude. Should we control emissions ? Yes. We had a huge defense establishment on the off chance of a Soviet attack. During the oil crisis in l973 the Japanese dealt with it by economizing their use of fossil fuels, their economy soared, and we had one of our more difficult periods. We need to understand how their economy improved when it became more energy-efficient. Personally we buy insurance. Why shouldn’t the whole planet do something ?”

       Kane’s colleague, Steve Zebiak, developed the first model for El Nino ten years ago, and is still working on it. He told me that “a change in the El Nino cycle and the weather it brings  could be the clearest  manifestation of global warming,” but pointed out that “El Nino has a rich spectrum of variability by itself. The events in recent years do not stand out as something beyond natural variability and due to increased CO2, but this is not to say that concept of global warming is not correct or that it could not be having an important impact on El Nino. We just don’t know how. It depends on changes in the deep ocean. It could get stronger or weaker. El Nino has global consequences, but it isn’t the only thing in the world.The North Atlantic oscillation and the monsoon have their own variability. But El Nino is the most important, strongest, and best understood source of year-to-year variability.” 

       If Zebiak’s seemed to be still grappling with his stance, Timothy Wirth offered a less ambiguous showbiz image : “El Nino is the trailer [the preview] of the movie, global warming.” But the strongest endorsement of a linkage came from Kevin Trenberth, at the National Atmospheric Research Center in Boulder, Colorado. “El Nino refers to a warming of the tropical Pacific Ocean and global warming is heating associated with an increase in greenhouse gases,” he told me in a telephone interview. “At this point, you simply can’t separate one type of warming from the other. They’re going to intersect and interfere with one another. It’s just a question of what form it’s going to take.”

*** 

        Trenberth’s described El Nino as “a key part of the climate system “ whose basic role is “to get heat out of the tropics.” This is also what the Gulf Stream does, and it, too, could be dramatically affected by global warming, if the horrific scenario “retrodicted” by Kane and Zebiak’s cantankerous colleague Wallace Broecker comes to pass. (Broecker resented having to take the time to explain his work to another ignorant layman, and this one  from a “woman’s magazine.” How dare I come to his office demanding an interview without having first familiarized himself with his work ? “You can call me an asshole. I don’t care what you print, but I’m not going to do this,” he kept prefacing his answers to my questions.) 

      By extrapolating core samples from the Greenland icecap Broecker has discovered that the  climate of the last eight thousand year has been remarkably stable— except for the last thirty years, during which it has been warming dramatically. Over the previous hundred thousand years there were often abrupt shifts ”suggesting that the Earth’s climate system has several distinct modes of operation and can shift from one to another in a matter of a decade or so,” he told me. Broecker fears we could be headed for such a system flip or reorganization : global warming could shut down the “oceanic conveyor belt” which transports heat from the West Indies to the British Isles via the Gulf Stream (because the melting of polar ice would disrupt the stream’s salt density gradient), in which case there would be a 10 degree drop in temperature, and London and Paris would become like Spitzbergen. “Whether there will be a warming I have no doubt,” Broecker told me. “But whether it will be on the high side or the low side, I can’t say. Possibly the whole thing will go unnoticed, or it will make the world so warm in the next hundred years that the ocean’s thermohaline circulation will experience a mode shift. If our mid-continental breadbaskets dry out we won’t be able to support the fifteen billion people expected by the end of the next century. Several degrees warmer could make the tropics uninhabitable, above our body temperature. What we’re doing is a gigantic experiment whose outcome we don’t know. We’re playing Russian roulette with the climate. The climate is an angry beast, and we’re poking it with sticks.” 

      Sir Robert May, the U.K.’s chief scientific adviser (“a small man with a lot to say,” as one of his colleagues describes him), is taking the possibility of the oceanic conveyor belt shutting down in the next hundred years very seriously. “The Gulf Stream transports toward the British Isles ‘free heat’ amounting to 27,000 times its total power-generation capacity,” he told me.  “There could be a huge drop in our temperature. Paradoxically, global warming could lead to sudden, drastic cooling. Carbon dioxide’s hundred-year residence time in the atmosphere is a huge argument for early action, because what is done today will be amplified out of all proportion in 50 years. But our institutions don’t cater to early action. They take a let’s wait and see attitude, and ten years could be the difference in being able to  rectify the situation.”

      “England’s weather records,” Sir Robert went on, “go back 337 years, and in the past ten years there have been three 500-year storms. The incidence of gales has increased 30%. Three of the last five years have been the warmest in our history.” He gave me a copy of his tersely-worded “Note on Climate Change,” which found that “the warming has, over the past couple of decades, extended beyond the bounds of our estimates of natural variability.” A statement that many of the more cautious atmospheric scientists are not yet ready to make.

       I asked about the impact of climate change on biodiversity. “In England it translates to asking the   wildlife species in our agricultural zones to get themselves up and move north fifty miles a decade, which is faster than anything in the fossil record,” Sir Robert told me. “Some species would be able to handle it and move smoothly.  But the blues and  the swallowtails [these are butterflies], which are tied to  particular patches of their food pants, can’t move that fast. You can’t move whole assemblages in time, and what will be lost is something more disturbing than just some pleasing natural artifacts for the emotional and spiritual gratification of societies that can afford  to appreciate them.”  (This reminded me of the time ten years ago when I was snorkeling off Madagascar and spotted large speckled cowrie sitting on the reef. Diving down, I grabbed it and holding it up to   the  local fishermen who had taken me out  in his outrigger, I gasped, “God, isn’t it beautiful,”  and he just looked at me with bemusement, as if to say, “Sure, boss, if you say so.”) 

.      “If you ask what are the services  that global ecosystems provide,” Sir Robert went on— “soil formation, water supplies, nutrient cycles, waste processing, pollution, and much else, they far exceed the global GNP. A major recent assessment has put a figure, necessarily very rough, for the economic value of ‘ecosystems services’ at between ten to 34 trillion pounds per year, with a best guess of 21 trillion pounds. This is roughly twice the conventional GNP, at around 11 trillion per year.”

       At the rate of fifty miles a decade, many of Britain’s species driven north by global warming will soon reach the edge of the land and  become extinct. Cases of climate-driven migration elsewhere are being carefully monitored : a Rocky Mountain butterfly called Edith’s checkerspot is  moving north with amazing speed, study plots on the floor of Monterey Bay that were set up in the thirties now have a completely different, southern California mix of seaweeds and invertebrates. Cases of alpine species being driven off mountaintops as the coniferous forests moves up their slopes and take over their summits are expected. Some of the unique endemic species driven off the “sky islands,” the isolated mountain ranges around Tucson, Arizona, will not be able  to make get across the interstate and will disappear, just as during the ice ages species driven south by the growing cold hit the massive wall of the Alps and died out at the base of the mountains. The outlook for the creation is not rosy.

***

         Another climate-driven disaster in the making that could dwarf even the shutting down of the Gulf Stream is the possibility that the Western Antarctic Ice Sheet might break off, which could happen at any time and would cause sea level to rise five to ten meters. “WAIS [as the people who are watching it refer to it] has not budged since warming began, but when it does start to slip, it will happen very fast, and a very large amount of ice will find itself in the ocean, and you can say goodbye to the Maldives and Bangladesh,” Elliot Norse told me. “The break-off will be a non-linear response to linear input. Nature works most often by the straw that breaks the camel principle, or as Malcolm X said of Kennedy’s assassination, by the chickens coming home to roost.”

        I contacted John Behrendt, an expert on  WAIS and a colleague of Kevin Trenberth at the NARC in Boulder. He began by explaining the difference between an ice shelf and an ice sheet. The Ross Ice Shelf is already floating. It freezes into pack ice in winter and is open in the summer. WAIS, however, is grounded, attached to the Ross Sea’s continental shelf, a marine-bed ice sheet that has been there for the last 20 or 30 million years, flowing off at its edge and being remade by snow. It is a huge chunk of snow and ice, 500 miles  long by 500 wide and about 9,000 feet thick (12,000 feet at its thickest point), about half of which is below sea level.  Six ice streams flow beneath it, and it is already sliding on mud, “like syrup poured on a table,” Behrendt explained, toward the Ross Ice Shelf and the open water beyond at the rate of 1200 feet a year. Global warming or the active volcanos under the sheet, could cause it to deglaciate, to break off and collapse, as happened with the Laurentide Ice Sheet a hundred thousand years ago and is happening now with the glaciers at the Glacier Bay National Park, Alaska, which are rapidly breaking off and slipping into the sea. “If WAIS deglaciates and surges out into the sea, sea level will equalize all over the earth at about six meters, or twenty feet, higher than it is now,” Behrendt estimated. “But it is controversial that it will even do this,” he cautioned, “and it would take several centuries at least to effect the rise. It’s the snow and ice that is above sea level that will break up into icebergs that will gradually melt and cause the rise.”  Whew, I thought. There’s time on this one. Norse had made it sound as if the rise could happen in a quickly as a year. 

      Behrendt suggested I talk to his colleague, Mark Meier, an authority on sea-level rise, for a second opinion. Meier told me that in the last 100 years the sea has been rising by about two millimeters a year— “more than in the past, and it will rise by more in the future. One third is due to the heating and expansion of the mix zone, the top hunded meters, one third is due to glaciers melting, and the other third is from what ? Tk.”. As far as WAIS was concerned, he confirmed that “it’s the top 4500 feet that matters,  and the expected sea level rise from their melting cannot happen quickly. It will take hundreds of years. But already,” he said, “global warming is causing many of the ice shelves that are already floating to break up and drift out to sea as icebergs. This will relieve some of the back pressure on the ice streams that feed the shelves and will draw down the ice sheets from the [Antarctic] continent. The mid-range estimate for sea-level rise over the next century is twenty inches.”

***  
    
Continue to page 8