Heat (27 page)

I call the Firewalking Institute of Research and Education. I reach the instructor. He is planning a training course in Argentina and another in California.

I ask him about walking on lava. “Charles Horton did it,” he tells me. Charles Horton is one of the big names in the firewalking movement, a name almost as well known as that of Tolly Burkan himself. Horton, the instructor tells me, was on a helicopter tour above the lava. He convinced the pilot to land so that he could walk on new ground. He took off his shoes and strolled across ground that had only recently lost its incandescent glow.

The instructor clearly envies Horton’s lava-walking experience. He hopes and plans to do it himself one day. He dreams of being surrounded by glowing rock, of feeling the heat beneath his feet and in the air around him.

“It would be mind blowing,” he says. And I agree.

Another day passes without lava on the surface.

In a rented convertible, we drive along the coast to the rainy side of the island, across the lower flank of the shield that is Mauna Loa, the earth’s largest active volcano, shorter than its inactive neighbor, Mauna Kea, but more massive, more voluminous, with something like ten thousand cubic miles of rock to its name.

Along certain stretches, the lava of the Mauna Loa shield is old and covered with rain forest, thick stands of dripping tree ferns and an abundance of bright flowers. Along these stretches, it is hard to see Mauna Loa as a volcano. The shield slopes lazily upward to the left and downward to the right, toward the sea, looking no more volcanic than Vermont.

Charles Darwin described a stratovolcano’s beautifully formed, smoking cone:

At about the same time, Herman Melville wrote skeptically of a shield volcano in the Marquesas Islands, two thousand miles from Hawaii:

In places, though, the route along the Mauna Loa shield changes from rain forest to bare and nearly bare hardened lava, unmistakably volcanic. After we pass through Hilo, turning west to connect with the Saddle Road and gaining altitude, we enter an almost lunar landscape of black rock. We move steadily upward on new pavement, a very good road. In clear patches we see the telescope domes on top of Mauna Kea, staring upward, but we pass into banks of fog and clouds and rain and are forced to put the top up, to seal off our convertible from the outside.

While stratovolcanoes may be more dangerous in terms of sudden explosions, of fast-moving pyroclastic flows, of overwhelming deposits of hot ash, shield volcanoes can still ruin your day. Slow-flowing lava leaves time to move the furniture out of the house, but the house still burns. Lava from Mauna Loa moved toward Hilo in 1935 and 1942. The lava formed tubes and troughs that conserved its heat, allowing it to flow long distances without hardening. The military was called in to bomb the flows, to break open the walls of tubes and troughs so that the lava would cool and harden or at least flow elsewhere, to someone else’s backyard. The lava, ignoring the bombings, stopped on its own. Hilo, in 1935 and 1942, was safe.

Twenty-one miles along the Saddle Road, high on the shoulder of the shield, we turn left onto a single-lane road of cracked concrete and potholes. We continue upward and leave all vegetation behind. We break out of the clouds above the rain. Now there is nothing but black and brown and yellow-tinted pahoehoe flows and scattered ‘a‘a flows, with lava on top of lava, flows from different events lying one on top of another, and on top of all of them this winding, wounded track that discourages speeding without the need for posted limits.

We stop and put the top down.

At the end of the road, we park beneath a sign that says “Observatory Trail.” This is not the astronomical observatory of Mauna Kea, which is north of here, on the other mountain, the neighboring volcano. This is the Mauna Loa Observatory, an atmospheric observatory.

But it is not just an atmospheric observatory. Arguably, it is
the
Atmospheric Observatory. It was here that Charles David Keeling kept his instruments. It was here that Keeling’s data grew into the Keeling Curve, not a curve at all but an icon, not a curve at all but a warning, not a curve at all but a climbing staircase of carbon dioxide over time, a graphical fact. It is a staircase climbing from 290 parts per million in the eighteenth century to about 310 parts per million when Keeling started his work in 1958 to close to 380 parts per million in 2005 when Keeling died, and nearly 390 parts per million today.

A man shows us around the facility. He has worked here since carbon dioxide levels were below 360 parts per million. That is to say, he has worked here for seventeen years.

We look at a plaque bolted to the side of a building, proclaiming that this is the Keeling Building. The building is more of a glorified shack than an institutional monument. It would be fair to say that the plaque is the Keeling Building’s finest feature. The plaque includes an embossed version of the Keeling Curve, from 1958 until 1997. The curve is an inclined, saw-toothed line, headed upward. The sawtooth pattern comes from seasonal changes in carbon dioxide. Levels go up in the winter when plants in the northern hemisphere senesce, and they go down in the summer when plants in the northern hemisphere are active. The overall trend is overwhelmingly upward. The data are so clear that they appear contrived. But they are not. They are measured data.

Above the Keeling Curve, the plaque reads: “Keeling Building: Named in honor of Professor Charles David Keeling, Scripps Institution of Oceanography, who initiated continuous CO
₂
measurements at this site in 1958.” The plaque is perhaps fifteen inches long by twelve inches tall.

Before Keeling came Jean Baptiste Joseph Fourier and John Tyndall, when carbon dioxide levels hovered around 290 parts per million. But these men were not so much concerned with human-induced climate change as they were with explaining the comings and goings of the glaciers that had once buried so much of what had become civilization.

Also well before Keeling, the Swedish chemist Svante Arrhenius took things one step further, working for months with a pencil and paper on mathematical calculations. Arrhenius had read Fourier’s work, and Tyndall’s. He began his 1896 paper with a simple statement: “A great deal has been written on the influence of the absorption of the atmosphere upon the climate.”

And this: “I should certainly not have undertaken these tedious calculations if an extraordinary interest had not been connected with them.”

That extraordinary interest was not future climate change but past climate change. Arrhenius’s interest—like that of Tyndall—stemmed from causes of past ice ages and past warm periods. “From geological researches the fact is well established that in Tertiary times there existed a vegetation and an animal life in the temperate and arctic zones that must have been conditioned by a much higher temperature than the present in the same regions. The temperature in the arctic zones appears to have exceeded the present temperature by about 8 or 9 degrees.” He computed that a doubling or tripling of carbon dioxide levels would raise temperatures about nine degrees, back to the levels he associated with the Tertiary. “In the Physical Society of Stockholm,” he wrote, “there have been occasionally very lively discussions on the probable causes of the Ice Age.” He calculated that roughly halving the levels of carbon dioxide would bring a return of the ice ages.

Arrhenius’s work faded into a footnote. Other explanations, more plausible explanations, were offered for the ice ages. Then, in 1938, came the English steam engineer Guy Callendar. “Few of those familiar with the natural heat exchanges of the atmosphere,” he wrote, “which go into the making of our climates and weather, would be prepared to admit that the activities of man could have any influence upon phenomena of so vast a scale. In the following paper I hope to show that such influence is not only possible, but is actually occurring at the present time.” He blamed the influence on fossil fuels: “By fuel combustion, man has added about 150,000 million tons of carbon dioxide to the air during the past half century.” He believed that he had data, collected from two hundred weather stations, showing a small increase in temperature.

But Callendar was no poster child for today’s climate change activists. He welcomed a warming climate. “In conclusion,” he wrote, “it may be said that the combustion of fossil fuel, whether it be peat from the surface or oil from 10,000 feet below, is likely to prove beneficial to mankind in several ways, besides the provision of heat and power. For instance, the above mentioned small increase of mean temperature would be important at the northern margin of cultivation.”

The warming would protect us from another ice age. In his words: “The deadly glaciers should be delayed indefinitely.”

His work was ignored. People were not ready to believe that humans could change the earth on such a monumental scale. Naysayers said his carbon dioxide measurements could not be trusted. They said his temperature measurements were flawed. The difficulty with Callendar’s thesis—one of the difficulties with his belief that humans could alter carbon concentrations in the atmosphere—was the ocean. Naysayers latched on to the world’s oceans. The oceans were vast enough to absorb tremendous amounts of carbon dioxide. The oceans would absorb carbon dioxide produced from fuels.

The oceans washed Callendar’s work into obscurity. Callendar became a sidebar in textbooks, a footnote.

Enter oceanographer Roger Revelle, twenty years later, in 1957. Revelle ran the Scripps Institution of Oceanography. Scripps then was a mere foreshadowing of Scripps today. It was Revelle who led the growth of Scripps into one of the best-known oceanographic laboratories in the world. Revelle was also an expert on the esoteric chemistry of carbon and calcium compounds in the ocean. With his knowledge, he was one of nearly a hundred scientists and technicians sent to Bikini Atoll to assess the effects of the hydrogen bomb test. Revelle assigned a few of the scientists to look at water chemistry. He was interested, too, in ocean mixing. He was interested in understanding the oceans as a potential receiving basin for radioactive waste. He studied the effects of a nuclear bomb used as a depth charge, a submarine killer, finding, among other things, that the contaminants from the bomb did not move quickly through the water column. Waste put into one layer of water might not readily spread to another. And carbon dioxide absorbed at the surface might not readily spread to the deeper layers. Most of the molecules of carbon dioxide finding their way into the surface waters would actually also find their way right back out, into the atmosphere.

Revelle’s work dismissed the naysayers who had dismissed Callendar. Revelle’s work reopened the possibility that carbon dioxide from the burning of fossil fuels was accumulating in the atmosphere. And it was Keeling’s follow-up, beginning around the same time that Revelle was publishing and talking about his work, that showed what was in fact happening. Keeling’s collection of samples and consistent measurements of carbon dioxide at the end of a long, rough road near the top of Mauna Loa showed, beyond doubt, accumulation of carbon dioxide.

Samples from other locations backed up Keeling’s work. There were samples from ships far at sea. There were samples from the whaling community of Barrow at the northern tip of Alaska. There were samples from the South Pole. There were samples from American Samoa and California. And in the end there was a plaque bolted to a glorified shed near the top of a volcano and an understanding that something big was going on.