Kilimanjaro Update The Indicator of Global Warming

The ice cap on Mount Kilimanjaro in Tanzania was formed almost eleven thousand years ago. Today, because of global warming, the ice cap is projected to disappear by 2020. Currently, eighty percent of the glacial ice on Kilimanjaro has melted, and in just 110 years (1910 - 2020) the ice cap will be gone. For glacial ice that took thousands of years to form to melt so quickly, one can only conclude that human activity during the last century has been a significant contributor to the change in the environment.

Kilimanjaro 1912

Kilimanjaro 2000

Our ability to influence a repair to the world environment may only be within the next few years. Without a significant global change in attitude and response to eliminate pollution, the world may soon enter an unrecoverable phase, bringing an uncontrollable demise to the Earth's ecology. If this occurs, no matter how hard we try, we will not be able to overcome the downward trend of the world's environment.

The scenario humanity must prevent is outlined in this paragraph. If global temperatures rise beyond previously recorded levels, the abnormally high heat will kill plant life. If a significant amount of vegetation dies due to high temperatures, the capacity for global conversion of CO2 to O2 on Earth will drop. Higher levels of CO2 will cause a further increase in Earth temperature and cause further plant destruction in a chain reaction. Global CO2 levels will then accelerate even higher, and vast areas will become deserts. Shortages of fresh water will occur and cause human populations to erode quickly. Even today, we may be close to entering this scenario. Scientists are already blaming the rise in ocean temperatures off the coast of Australia for the significant decline of the coral along the Great Barrier Reef.

Throughout the world, many species of plants and animals that took millions of years to evolve have already died because of pollution. There are 11000 species of plants and animals threatened at this very moment, and most from the destructive influences of air and water pollution created by humanity. Conservation of the planet and the building of environmental economic infrastructures to save it are essential. We have the intellect to survive, but are currently taking little decisive action to create sustainability for ourselves.

Working together within the United Nations, humanity could plan a solution for the Earth where all of us live with close to zero impact on the environment. The Earth will save us if we save it. Wars and religious differences must be overcome so that mankind can rapidly chart an economic path for survival. Humans are just one organic element on Earth, and the other animals, plants and micro-organisms are essential for our existence.

From an economic perspective, the restoration of the Earth will only occur when the word 'profit' is equated to environmental restoration and sustainability. The greatest challenge we have ever faced in our human existence is whether we have the capacity to collectively save the planet. We must act while we still have a chance!

The shrinking glacier is an iconic image of global climate change. Rising temperatures may reshape vegetation, but such changes are visually subtle on the landscape; by contrast, a vast glacier retreated to a fraction of its former grandeur presents stunning evidence of how climate shapes the face of the planet. Viewers of the film An Inconvenient Truth are startled by paired before-and-after photos of vanishing glaciers around the world. If those were not enough, the scars left behind by the retreat of these mountain-grinding giants testify to their impotence in the face of something as insubstantial as warmer air.

But the commonly heard—and generally correct—statement that glaciers are disappearing because of warming glosses over the physical processes responsible for their disappearance. Indeed, warming fails spectacularly to explain the behavior of the glaciers and plateau ice on Africa's Kilimanjaro massif, just 3 degrees south of the equator, and to a lesser extent other tropical glaciers. The disappearing ice cap of the "shining mountain," which gets a starring role in the movie, is not an appropriate poster child for global climate change.

The fact that glaciers exist in the tropics at all takes some explaining. Atmospheric temperatures drop about 6.5 degrees Celsius per kilometer of altitude, so the air atop a 5,000-meter mountain can be 32.5 degrees colder than the air at sea level; thus, even in the tropics, high-mountain temperatures are generally below freezing. The climber ascending such a mountain passes first through lush tropical vegetation that gradually gives way to low shrubs, then grasses and finally a zone that is nearly devoid of vegetation because water is not available in liquid form. Tropical mountaintop temperatures vary only a little from season to season, since the sun is high in the sky at midday throughout the year. With temperatures this low, snow accumulates in ice layers and glaciers on Kilimanjaro, Mount Kenya and the Rwenzori range in East Africa, on Irian Jaya in Indonesia and especially in the Andean cordillera in South America, where 99.7 percent of the ice in tropical glaciers is found.

A simple, physically accurate way to understand the processes creating and controlling these and other glaciers is to think in terms of their energy balance and mass balance.

Mass balance is merely the difference between accumulation (mass added) and ablation (mass subtracted); in this case mass refers to water in its solid, liquid or vapor form. A glacier's mass is closely related to its volume, which can be calculated by multiplying its area by its average depth. When a glacier's volume changes, a change in length is usually the most obvious and well-documented evidence. Alaska's vanishing Muir Glacier, an extreme case, shrank more than 2 kilometers in length over the past half-century.

Glaciers never quite achieve "balance" but rather wobble like a novice tightrope walker. Sometimes a change in climate throws the glacier substantially out of balance, and its mass can take decades to reach a new equilibrium.

Added mass comes largely from the atmosphere, generally as snowfall but also as rainfall that freezes; in rare cases mass is added by riming, in which wind carries water droplets that are so cold that they freeze on contact.

The most obvious subtractive process is the runoff of melted water from a glacier surface. Another process that reduces glacial mass is sublimation, that is, the conversion of ice directly to water vapor, which can take place at temperatures well below the melting point but which requires about eight times as much energy as melting. Sublimation occurs when the moisture in the air is less than the moisture delivered from the ice surface. It is the process responsible for "freezer burn," when improperly sealed food loses moisture.

Observations of Kilimanjaro's ice from about 1880 to 2003 allow us to quantify changes in area but not in mass or volume. The early European explorers Hans Meyer and Ludwig Purtscheller were the first to reach the summit in 1889. Based on their surveys and sketches, but mainly from moraines identified with aerial photographs, Henry Osmaston reconstructed (in 1989) an 1880 ice area of 20 square kilometers. In 1912, a precise 1:50,000 map based on terrestrial photogrammetry done by Edward Oehler and Fritz Klute placed the area at 12.1 square kilometers. By 2003 that area had declined to 2.5 square kilometers, a shrinkage of almost 90 percent. Much of that decline, though, had already taken place by 1953, when the area was 6.7 square kilometers (down 66 percent from 1880). Over the same period, ice movement has been almost nil on the plateau and slight on the slopes. There are indications that the slope glaciers at least are coming into equilibrium.

This pacing of change is at odds with the pace of temperature changes globally, which have been strongly upward since the 1970s after a period of stasis. Other glaciers share this pacing, with many coming into equilibrium or even advancing around the 1970s before beginning a sharp retreat.

Temperature trends are difficult to evaluate, owing to the paucity of relevant measurements, but taken together the data presented in the 2007 report from the IPCC (Intergovernmental Panel on Climate Change) suggest little trend in local temperature during the past few decades. In the East African highlands far below Kilimanjaro's peaks, temperature records suggest a warming of 0.5-0.8 degree during 1901-2005, a nontrivial amount of warming but probably larger than the warming at Kibo's peak. For the free troposphere, a deep layer including Kibo's peak, the warming rate during the period 1979-2004 for the zone 20 degrees latitude north and south of the equator was less than 0.1 degree per decade—smaller than the surface trend for that time and not statistically different from zero. Averages over a deep layer of the atmosphere, however, may be a poor estimate of the warming at Kilimanjaro's peak, although it has been argued that the warming must be nearly the same at all longitudes in the tropics, given that rotational effects are small, imposing strong dynamical constraints.

Focusing on measurements of air temperatures at the 500-millibar air-pressure level (roughly 5,500 meters altitude) from balloons, one paper suggests a warming trend in the tropical middle troposphere from about 1960 to 1979, followed by cooling from 1979 to 1997, although this study has not been updated.

Two of the data sets used to derive the tropical averages above are "reanalysis" data sets, in which observations are fed into a global dynamical model, thereby providing dynamically consistent fields of temperature, winds and so on, even where there are no observations. At the reanalysis point closest to Kilimanjaro's peak, there seems to be no trend since the late 1950s. But like the balloon and satel-lite data, the reanalysis data can be unsuitable for documenting trends over time .

When pieced together, these disparate lines of evidence do not suggest that any warming at Kilimanjaro's summit has been large enough to explain the disappearance of most of its ice, either during the whole 20th century or during the best-measured period, the last 25 years.

Glaciers and Global Climate
The observations described above point to a combination of factors other than warming air—chiefly a drying of the surrounding air that reduced accumulation and increased ablation—as responsible for the decline of the ice on Kilimanjaro since the first observations in the 1880s. The mass balance is dominated by sublimation, which requires much more energy per unit mass than melting; this energy is supplied by solar radiation.

These processes are fairly insensitive to temperature and hence to global warming. If air temperatures were eventually to rise above freezing, sensible-heat flux and atmospheric long-wave emission would take the lead from sublimation and solar radiation. Since the summit glaciers do not experience shading, all sharp-edged features would soon disappear. But the sharp-edged features have persisted for more than a century. By the time the 19th-century explorers reached Kilimanjaro's summit, vertical walls had already developed, setting in motion the loss processes that have continued to this day.

An additional clue about the pacing of ice loss comes from the water levels in nearby Lake Victoria. Long-term records and proxy evidence of lake levels indicate a substantial decline in regional precipitation at the end of the 19th century after some considerably wetter decades. Overall, the historical records available suggest that the large ice cap described by Victorian-era explorers was more likely the product of an unusually wet period than of cooler global temperatures.