Science

In a new paper published in the International Journal of Climatology (24; 329-339), Georg Kaser of the University of Innsbruck and colleagues from the University of Massachussets, Amherst, and the Tanzania Meteorological Agency provide more proof that the snows of Kilimanjaro are disappearing owing to factors other than global warming.

In “Modern Glacier Retreat on Kilimanjaro as Evidence of Climate Change: Observations and Facts,” Kaser et al. “develop a new concept for investigating the retreat of Kilimanjaros glaciers, based on the physical understanding of glacierclimate interactions.”

They say, “The concept considers the peculiarities of the mountain and implies that climatological processes other than air temperature control the ice recession in a direct manner. A drastic drop in atmospheric moisture at the end of the 19th century and the ensuing drier climatic conditions are likely forcing glacier retreat on Kilimanjaro.”

The authors reference another study, soon to be published in the Journal of Geophysical Research. According to them, “Mlg and Hardy (2004) show that mass loss on the summit horizontal glacier surfaces is mainly due to sublimation (i.e. turbulent latent heat flux) and is little affected by air temperature through the turbulent sensible heat flux.”

In a case of the bugbear of the 1980s meeting the hobgoblin of the 1990s, scientists have found that acid rain can slow global warming by reducing methane emissions from natural wetland areas.

The new study, led by Vincent Gauci of Britains Open University together with colleagues at NASA and published in Proceedings of the National Academy of Sciences, finds that acid rain counteracts the natural production of methane gases by microbes in wetland areas.

As New Scientist says (Aug. 3), “Methane is thought to account for 22 percent of the human-enhanced greenhouse effect. And microbes in wetland areas are its biggest producers. They feed off substrates such as hydrogen and acetate in peat and emit methane into the atmosphere.”

The theory is that global warming itself will speed up the production of methane, “as heating up the microbes causes them to produce even more methane. But the new model suggests that sulphur [sic] pollution from industry cancels this out. This is because sulphur-eating bacteria also found in wetland regions outcompete the methane-emitting microbes for substrates. Experiments have shown that sulphur deposits can reduce methane production in small regions by up to 30 per cent by activating sulphur-eating bacteria.”

Atmospheric concentrations of methane have leveled off in the past few years.

Extreme weather conditions in the Great Plains, specifically dust bowls, have long been a natural occurrence, according to a recent Duke University study.

Jim Clark, H.L. Blomquist Professor of Biology at Duke Universitys Nicholas School of the Environment and Earth Sciences, summarizes: “What would happen was that the grass would disappear [because of naturally occurring droughts]. So the fuel for fire would be lost. We’d see the erosion start. The chemistry of the lakes would change. We would see these dust-bowl effects. And then, within several decades to a century later, the grasses would come back, fires would start back up and erosion would stop.”

According to Clark, the regularity of these ancient droughts make much more recent Great Plains droughts in the 1890s and 1930s appear “unremarkable” by comparison, even though the contemporary ones “walloped people.” An understanding that extreme weather events have long occurred seriously puts in to question environmentalists assumptions that human activity causes extreme weather events. In fact, Clark went so far as to say, “It’s not only climate change from changing CO2 content in the atmosphere, but also this natural variability out there that we don’t fully understand.” (Duke University press release, Aug. 2).