Climate Blame, Climate Responsibility

Opinion by Christopher White


When members of the U.N. Intergovernmental Panel on Climate Change (IPCC) assemble in Stockholm later this month (September 23-26) to begin approval of their fifth global assessment since 1988, climate deniers will likely be on their minds. Global warming skeptics heavily criticized the Fourth Assessment (2007) for minor errors and high-end predictions in some future scenarios. The panelists are striving for accuracy in the new round, but climate change advocates fear the IPCC may, in light of the previous criticism, go too far with their caution and actually water down some of the findings. Michael Mann, Professor at Penn State University and as a member of the IPCC, one of the recipients of the Nobel Peace Prize in 2007, worries the panel may have been influenced by climate skeptics in drafting its report. “I think the IPCC… has…erred in understating the degree of the likely changes,” Mann said in August. He called for scientific integrity, though allegiance to facts is no deterrent to criticism. If the past is prologue, as soon as the final Fifth Assessment is published in 2014, more attacks will be launched by contrarians. It is likely that the drafting of this offensive will be underway before anyone has read the report.

Ammunition is waiting in the wings. Climate deniers have a long shopping list of surrogates for carbon loading by humans, substituting blame for warming onto everything from solar flares to cosmic rays. They claim carbon dioxide is not a pollutant. But few in the scientific community are buying. Some of these theories spring from quasi-science, others from wishful thinking. Doubters have claimed that a new ice age is coming, when thermometers around the planet speak a different story.

Year by year, science affirms the reality of global climate change from the release of greenhouse gases. Meanwhile, the validity of at least one secondary influence has recently been confirmed. A new study from NASA’s Jet Propulsion Laboratory points to soot and dust as a major culprit for the melting of glaciers in the European Alps in the early days of the Industrial Revolution. Climate doubters are already seizing upon this study as “proof” that global warming is not caused by elevated levels of carbon dioxide. In fact, soot, also known as black carbon, ranks second to carbon dioxide as the impetus for rising temperatures. Black carbon, mostly from wood stoves, remains in the atmosphere for weeks or months, while carbon dioxide accumulates for centuries. Carbon dioxide is thought responsible for 40 percent of warming, compared to 18 percent for black carbon. Still, climate naysayers take a reductionist view: only one cause—soot—is in play. The climate change story, however, is more complex. Methane and nitrous oxide also register as greenhouse gases.

Despite the complexity, each component can be tracked. This past spring, the level of carbon dioxide in the atmosphere surpassed an average daily concentration of 400 parts per million (ppm), the first time it had topped that threshold in at least three million years. As a heat-trapping gas, carbon dioxide is believed primarily responsible for the elevation of global temperatures over the past one hundred or more years—most obviously witnessed during the decade 2000-2009, which for the United States was the warmest on record. Evidence from bubbles in Antarctic ice suggests global temperatures and carbon dioxide levels have been closely linked since before man arrived on Earth. Now, with the burning of fossil fuels, the correlation today is tied to the runaway growth of civilization and industry.

Nowhere is the manifestation of that correlation more visible than the melting of alpine glaciers in mountain ranges around the world. The Andes have lost 20 percent of their glacier volume since 1970; the European Alps have lost more than 60 percent since 1850. Mountain glaciers are disappearing faster than polar ice but in the long run will not have as large an impact on sea level change. Polar ice is more massive. However, alpine glaciers are more relevant in other ways. They contribute to more than 50 percent of civilization’s water supplies. An interruption to that source would reek havoc. They are also one of the best indicators of climate change: the waxing and waning of alpine ice closely follows the fall and rise of temperatures.

One notable example of this signal is the ice in Glacier National Park (GNP). In 1850, there were 150 glaciers in the region that would become the Park in 1910. Today only twenty-five survive. Scientists estimate the remaining glaciers may have as little as a decade left. Impacts downstream are already apparent. Fish and aquatic insects are in trouble. Avalanches are more frequent. Forests are tinder dry. Many climate watchers are looking toward GNP as the vanguard of what’s to come overseas from Kilimanjaro to the Himalayas.

A modeling experiment by scientists at the University of Zurich has shown that the European Alps could lose 80 percent of their ice by the end of this century, if summer temperatures rise by 5 degrees Fahrenheit. In the Fourth Assessment (2007), a doubling of the carbon dioxide level in the atmosphere (from pre-Industrial levels) was linked to a minimum 3.6-degree rise in temperature, but many climate scientists suggest a 5-degree rise is more likely. In either case, much of Europe’s ice, as well as that of the Rockies and Cascades, will melt. Without drastic cuts in carbon emissions, the doubling is likely at the end of this century. The concentration of carbon dioxide has already increased 41 percent since the Industrial Revolution. Under most scientists’ forecasts, a doubling would result in significant melting of polar ice caps, heat waves, wildlife extinctions, and disruption of agriculture in many countries.

With every new IPCC assessment, the scientific consensus for climate change by anthropogenic means becomes more robust. In its wake, the denial troops are becoming more shrill. Like the opponents of evolution, plate tectonics, and a sun-centered solar system, the climate contrarians scream loudest when the consensus is about to become common wisdom. The Fifth Assessment (2014) will reportedly place new emphasis on the melting of ice sheets and sea level changes, as well as on ocean acidification, which is damaging coral reefs and interrupting marine food chains. The advent of soot will also gain mention. Such a comprehensive appraisal of climate change impacts will be welcome. Over 830 scientists from 195 countries will eventually contribute to the report. The draft assessment that the IPCC will be editing in Stockholm states that the odds are at least 95 percent that humans are the principal cause of global warming. The level of confidence should embolden the panelists to hold their ground. Let’s stick to the science and leave the deniers to their dust.