Peer Reviewed Articles About Climate Change and How Its Affecting Glaciers

• Journal List
• Behav Anal
• 5.33(two); Fall 2010
• PMC2995507

Behav Anal. 2010 Fall; 33(ii): 153–170.

Climate Alter: The Show and Our Options

Abstruse

Glaciers serve as early indicators of climate change. Over the final 35 years, our research squad has recovered ice-core records of climatic and environmental variations from the polar regions and from low-breadth high-top ice fields from 16 countries. The ongoing widespread melting of high-elevation glaciers and water ice caps, particularly in low to middle latitudes, provides some of the strongest evidence to date that a large-scale, pervasive, and, in some cases, rapid change in Earth'southward climate system is underway. This paper highlights observations of 20th and 21st century glacier shrinkage in the Andes, the Himalayas, and on Mountain Kilimanjaro. Ice cores retrieved from shrinking glaciers around the world ostend their continuous existence for periods ranging from hundreds of years to multiple millennia, suggesting that climatological weather condition that boss those regions today are dissimilar from those under which these ice fields originally accumulated and have been sustained. The current warming is therefore unusual when viewed from the millennial perspective provided by multiple lines of proxy bear witness and the 160-twelvemonth record of direct temperature measurements. Despite all this bear witness, plus the well-documented continual increase in atmospheric greenhouse gas concentrations, societies have taken piffling action to address this global-scale problem. Hence, the rate of global carbon dioxide emissions continues to advance. Equally a consequence of our inaction, nosotros have three options: mitigation, adaptation, and suffering.

Keywords: climate, global warming

Climatologists, like other scientists, tend to be a stolid group. We are not given to theatrical rantings about falling skies. Near of united states of america are far more comfortable in our laboratories or gathering data in the field than nosotros are giving interviews to journalists or speaking before Congressional committees. Why then are climatologists speaking out about the dangers of global warming? The answer is that near all of us are now convinced that global warming poses a articulate and present danger to civilization ("Climatic change," 2010).

That bold statement may seem similar hyperbole, but there is now a very clear pattern in the scientific evidence documenting that the earth is warming, that warming is due largely to human activity, that warming is causing of import changes in climate, and that rapid and potentially catastrophic changes in the nigh futurity are very possible. This pattern emerges non, as is so ofttimes suggested, just from computer simulations, merely from the weight and balance of the empirical show as well.

THE Testify

Effigy 1 shows northern hemisphere temperature profiles for the final 1,000 years from a diverseness of high-resolution climate recorders such as glacier lengths (Oerlemans, 2005), tree rings (Briffa, Jones, Schwerngruber, Shiyatov, & Cook, 2002; Esper, Cook, & Schweingruber, 2002), and combined sources that include some or all of the following: tree rings, sediment cores, ice cores, corals, and historical records (Crowley & Lowery, 2000; Jones, Briffa, Barnett, & Tett, 1998; Mann, Bradley, & Hughes, 1999; Moberg, Sonechkin, Holmgrem, Datsenko, & Karlen, 2005). The heavy gray line is a composite of all these temperatures (Mann & Jones, 2003), and the heavy black line depicts actual thermometer readings back to 1850 (see National Research Council, 2006, for a review of surface temperature reconstructions). Although the diverse curves differ from one another, their general shapes are like. Each data source shows that average northern hemisphere temperatures remained relatively stable until the late 20th century. It is the agreement of these various information sets and the design that make climatologists confident that the warming trend is real.

A variety of temperature records over the concluding ane,000 years, based on a variety of proxy recorders such as tree rings, ice cores, historical records, instrumental data, etc., shows the extent of the recent warming. The range of temperature projected by Meehl et al. (2007) to 2100 Advertizement is shown past the shaded region, and the average of the range is depicted by the filled circle.

Because these temperature numbers are based on northern hemisphere averages, they do not reflect regional, seasonal, and altitudinal variations. For instance, the average temperature in the western United States is rising more quickly than in the eastern function of the country, and on boilerplate winters are warming faster than summers (Meehl, Arblaster, & Tebaldi, 2007). The almost severe temperature increases appear to be full-bodied in the Arctic and over the Antarctic Peninsula too as within the interior of the big continents. This variability complicates matters, and adds to the difficulty of disarming the public, and even scientists in other fields, that global warming is occurring. Considering of this, information technology may exist useful to examine another kind of evidence: melting ice.

Retreat of Mountain Glaciers

The globe's mountain glaciers and ice caps incorporate less than iv% of the world'southward ice comprehend, but they provide invaluable information about changes in climate. Because glaciers are smaller and thinner than the polar water ice sheets, their ratio of surface surface area to volume is much greater; thus, they respond more quickly to temperature changes. In addition, warming trends are amplified at college altitudes where nearly glaciers are located (Bradley, Keimig, Diaz, & Hardy, 2009; Bradley, Vuille, Diaz, & Vergara, 2006). Thus, glaciers provide an early on alarm system of climate change; they are our "canaries in the coal mine."

Consider the glaciers of Africa's Mount Kilimanjaro (Figure ii). Using a combination of terrestrial photogrammetric maps, satellite images, and aerial photographs, we take determined that the ice fields on Kibo, the highest crater on Kilimanjaro, accept lost 85% of their coverage since 1912 (Thompson, Brecher, Mosley-Thompson, Hardy, & Marking, 2009).

The retreat of glaciers on Mount Kilimanjaro tin be seen in the photographs from 1912, 1970, 2000, and 2006; from 1912 to 2006, 85% of the ice has disappeared.

Figure 3 shows a series of aerial photographs of Furtwängler glacier, in the center of Kibo crater, taken between 2000 and 2007, when the glacier dissever into two sections. Every bit Furtwängler recedes, it is also thinning rapidly, from 9.5 m in 2000 to 4.seven m in 2009 (for more images of Furtwängler's retreat, run across http://www.examiner.com/examiner/10-10722-Orlando-Scientific discipline-Policy-Examiner∼y2009m11d2-Mt-Kilimanjaros-Furtwängler-Glacier-in-retreat). If y'all connect the dots on the changes seen to date and presume the aforementioned rate of loss in the hereafter, within the adjacent decade many of the glaciers of Kilimanjaro, a Swahili word meaning "shining mount," will have disappeared.

Deterioration of the Furtwängler glacier in the center of Kibo crater on Mount Kilimanjaro. Since 2000 the ice field has decreased in size and thickness and has divided in 2.

The Quelccaya ice cap, which is located in southern Peru next to the Amazon Bowl, is the largest tropical water ice field on Globe. Quelccaya has several outlet glaciers, glaciers that extend from the edges of an ice cap like fingers from a hand. The retreat of one of these, Qori Kalis, has been studied and photographed since 1963. At the beginning of this study, Qori Kalis extended 1,200 m out from the ice cap, and at that place was no melt water at the finish (Figure four, map top left). By the summer of 2008, Qori Kalis had retreated to the very edge of Quelccaya, leaving backside an 84-acre lake, 60 g deep. Over the years, a bedrock almost the base camp has served every bit a benchmark confronting which to tape the changes in the position of the border of the ice. In 1977 the water ice was actually pushing against the bedrock (Figure v, top), merely by 2006 a substantial gap had appeared and been filled by a lake (Figure five, bottom). Thus, the loss of Quelccaya's ice is not only on the Qori Kalis glacier simply besides on the margin of the ice cap itself. Since 1978, about 25% of this tropical water ice cap has disappeared.

Retreat of the Qori Kalis outlet glacier on the Quelccaya ice cap. Each line shows the extent of the ice. The photos along the lesser provide a pictorial history of the melting of the Qori Kalis outlet glacier and the formation of a lake. The retreat of Qori Kalis is like to the loss of several Peruvian glaciers, as shown in the graph insert.

Top: photo taken in 1978 shows a margin of the Quelccaya ice cap pushing against a boulder. Lesser: the aforementioned margin is shown in a 2005 photo. The water ice has receded and has been replaced by a small-scale lake. The bedrock shown in the height photo is located in the heart of the white circle to the right.

The Himalayan Mountains are home to more than 15,000 glaciers. Unfortunately, only a few of these glaciers have been monitored over an extended menses, and so reliable basis observations that are crucial for determining regional retreat rates do not yet be. Nonetheless, a recent study of an ice core from the Naimona'nyi glacier in the southwestern Himalayas (Kehrwald et al., 2008) shows that ice is disappearing from the top of the glacier, as shown by the lack of the radioactive bomb layers from the 1950s and early 1960s that announced in all Tibetan and Himalayan water ice cadre records (Thompson, 2000; Thompson et al., 1990, 1997, 2006).

Glaciologists at the Plant of Tibetan Plateau Research in Beijing have been monitoring 612 glaciers across the High Asian region since 1980. These scientists found that from 1980 to 1990, 90% of these glaciers were retreating; from 1990 to 2005, the proportion of retreating glaciers increased to 95% (Yao, Pu, Lu, Wang, & Yu, 2007).

A study of 67 glaciers in Alaska from the mid-1950s to the mid-1990s shows that all are thinning (Arendt, Echelmeyer, Harrison, Lingle, & Valentine, 2002). In northern Alaska's Brooks Range, 100% of the glaciers are in retreat, and in southeastern Alaska 98% are shrinking (Molnia, 2007). Glacier National Park in Montana independent more than than 100 glaciers when it was established in 1910. Today, simply 26 remain, and at the current rate of subtract it is estimated that past 2030 there will be no glaciers in Glacier National Park (Hall & Fagre, 2003). The oldest glacier photos come up from the Alps. Ninety-nine percent of the glaciers in the Alps are retreating, and 92% of Republic of chile's Andean glaciers are retreating (Vince, 2010).

The pattern described here is repeated around the earth. Mountain glaciers about everywhere are retreating.

Loss of Polar Water ice

Satellite documentation of the area covered by sea ice in the Arctic Ocean extends back three decades. This expanse, measured each September, decreased at a charge per unit of virtually 8.six% per decade from 1979 to 2007. In 2007 solitary, 24% of the ice disappeared. In 2006 the Northwest Passage was ice free for the starting time time in recorded history.

Every bit noted before, polar ice sheets are slower to respond to temperature rise than the smaller mount glaciers, but they, also, are melting. The Greenland ice sheet has also experienced dramatic ice cook in contempo years. At that place has been an increment in both the number and the size of lakes in the southern office of the ice sheet, and crevices can serve as conduits (chosen moulins) that transport meltwater rapidly into the glacier. H2o has been observed flowing through these moulins downward to the bottom of the water ice sheet where information technology acts as a lubricant that speeds the menstruation of ice to the ocean (Das et al., 2008; Zwally et al., 2002).

The water ice in Antarctica is also melting. The late John Mercer, a glacial geologist at The Ohio State University, long ago concluded that the commencement bear witness of global warming due to increasing carbon dioxide (CO₂) would be the breakup of the Antarctic ice shelves (Mercer, 1978). Mean temperatures on the Antarctic Peninsula take risen 2.v° C (iv.5° F) in the last 50 years, resulting in the breakup of the ice shelves in just the way Mercer predicted. One of the most rapid of these shelf deteriorations occurred in 2002, when the Larsen B, a trunk of water ice over 200 m deep that covered an surface area the size of Rhode Island, complanate in just 31 days (see images http://earthobservatory.nasa.gov/IOTD/view.php?id = 2351). An ice shelf is substantially an iceberg attached to land water ice. Just as an ice cube does not raise the h2o level in a drinking glass when information technology melts, so a melting water ice shelf leaves sea levels unchanged. But water ice shelves serve as buttresses to glaciers on country, and when those ice shelves plummet information technology speeds the menstruation of the glaciers they were belongings back into the bounding main, which causes sea level to ascent apace.

Just days before this paper went to press, a giant ice island four times the size of Manhattan broke off the Petermann glacier in Greenland. This issue lone does not prove global climatic change, because half of the ice loss from Greenland each year comes from icebergs calving from the margins. It is the fact that this outcome is part of a long-term tendency of increasing rates of ice loss, coupled with the fact that temperature is increasing in this region at the rate of 2° C (3.6° F) per decade, that indicates that larger scale global climate change is underway.

The loss of ice in the Arctic and Antarctic regions is particularly troubling because these are the locations of the largest ice sheets in the earth. Of the land ice on the planet, 96% is found on Greenland and Antarctica. Should all this ice melt, sea level would rise over 64 yard (Church et al., 2001; Lemke et al., 2007), and of class the actual bounding main level would be much higher due to thermal expansion of the world's oceans as they warm.

Although research shows some variability in the charge per unit of ice loss, information technology is clear that mount glaciers and polar water ice sheets are melting, and there is no plausible explanation for this but global warming. Add to this the laboratory bear witness and the meteorological measurements, and the case for global warming cannot be denied. And then what causes global temperatures to rise?

CAUSES OF GLOBAL WARMING

Climatologists strive to reconstruct by climate variations on regional and global scales, but they also try to determine the mechanisms, called forcers, that bulldoze climate change. Climatologists recognize 2 basic categories of forcers. Natural forcers are recurring processes that take been around for millions of years; anthropogenic forcers are more recent processes caused past human activeness.

1 familiar natural forcer is the earth's orbit effectually the sun, which gives the states our seasons. In the northern hemisphere, June is warm because the lord's day'southward rays fall more directly on information technology, and the sun appears high in the heaven; in the southern hemisphere, June is absurd because the sunday's rays hit the world at a deep angle, and the sun appears low in the sky.

Less obvious natural forcers include brusque- and long-term changes in the temper and ocean. For example, when Mount Pinatubo erupted in the Philippines in 1991, it spewed millions of tons of sulfuric gases and ash particles loftier into the atmosphere, blocking the sun'due south rays. This lowered global temperatures for the next few years. Another natural forcer is the linked oceanic and atmospheric system in the equatorial Pacific Ocean known every bit the El Niño-Southern Oscillation (ENSO). ENSO occurs every 3 to 7 years in the tropical Pacific and brings warm, wet weather to some regions and absurd, dry atmospheric condition to other areas.

Other natural forcers include periodic changes in free energy from the sun. These include the 11- to 12-twelvemonth sunspot bicycle and the 70- to 90-year Wolf-Gleissberg cycle, a modulation of the aamplitude of the 11-year solar cycle. These changes in solar energy can impact atmospheric temperature across large regions for hundreds of years and may have acquired the "medieval climate bibelot" in the northern hemisphere that lasted from nigh 1100 Advert to 1300 AD. Solar cycles may also have played a part in the crusade of the "fiddling ice historic period" in N America and Europe during the 16th to 19th centuries. These changes in climate, which are often cited by those who dismiss global warming as a normal, cyclical outcome, afflicted large areas, only not the Earth every bit a whole. The medieval climate anomaly showed warmth that matches or exceeds that of the past decade in some regions, but it fell well below recent levels globally (Mann et al., 2009).

The about powerful natural forcers are variations in the orbit of the Earth effectually the Sunday, which final from 22,000 to 100,000 years. These "orbital forcings" are partly responsible for both the ice ages (the glacial periods during which large regions at high and midddle latitudes are covered by thick ice sheets), and for the warm interglacial periods such as the nowadays Holocene epoch which began nigh 10,000 years ago.

There is consensus among climatologists that the warming tendency we have been experiencing for the past 100 years or so cannot be accounted for past whatsoever of the known natural forcers. Sunspot cycles, for example, can increase the sun's output, raising temperatures in our atmosphere. Nosotros are seeing a temperature increase in the troposphere, the lower level of our temper, and a temperature subtract in the stratosphere, the upper level. But this is the exact opposite of what we would get if increased solar free energy were responsible. Similarly, global temperatures have increased more than at dark than during the day, again the opposite of what would occur if the dominicus were driving global warming. In addition, temperatures have risen more in winter than in summertime. This, too, is the opposite of what would be expected if the sun were responsible for the planet'due south warming. High latitudes take warmed more than low latitudes, and because we get more than radiation from the sun at low latitudes, we over again would expect the opposite if the sun were driving these changes. Thus, changes in solar output cannot account for the electric current period of global warming (Meehl et al., 2007). ENSO and other natural forcers also neglect to explicate the steady, rapid rise in the earth's temperature. The inescapable decision is that the rise in temperature is due to anthropogenic forces, that is, human behavior.

The relatively mild temperatures of the past ten,000 years have been maintained past the greenhouse outcome, a natural miracle. As orbital forcing brought the last ice historic period to an end, the oceans warmed, releasing CO₂ into the atmosphere, where it trapped infrared energy reflected from the globe's surface. This warmed the planet. The greenhouse outcome is a natural, self-regulating process that is absolutely essential to sustain life on the planet. Still, it is not immutable. Change the level of greenhouse gases in the atmosphere, and the planet heats up or cools down.

Greenhouse gases are captured in ice, so ice cores allow us to run into the levels of greenhouse gases in ages past. The longest water ice cadre ever recovered (from the European Project for Ice Coring in Antarctica) takes us 800,000 years back in time, and includes a history of CO₂ and methane levels preserved in bubbles in the water ice (Loulergue et al., 2008; Lüthi et al., 2008). The CO_two and methane curves illustrated in Figure 6 show that the modernistic levels of these gases are unprecedented in the final 800 millennia.

Concentrations of carbon dioxide (CO₂) and methane (CH₄) over the concluding 800,000 years (8 glacial cycles) from E Antarctic water ice cores. Data from Loulergue et al. (2008) and Lüthi et al. (2008). The current concentrations of CO₂ and CH₄ are also shown (Forster et al., 2007).

Globally, CO₂ concentrations have varied between 180 and 190 parts per million per volume (ppmv) during glacial (cold) periods and between 270 and 290 ppmv during interglacial (warm) periods. However, since the onset of the Industrial Revolution, when fossil fuel use (chiefly coal and oil) began to burgeon, CO_two concentration has increased almost 38% over the natural interglacial levels (Forster et al., 2007). Between 1975 and 2005, CO₂ emissions increased 70%, and between 1999 and 2005 global emissions increased 3% per year (Marland, Boden, & Andres, 2006). As of this writing, the CO₂ concentration in the atmosphere is 391 ppmv (Mauna Loa CO₂ annual mean data from the National Oceanic and Atmospheric Administration, 2010), a level non seen at any time in 800,000 years. Climatologists have identified no natural forcers that could account for this rapid and previously unseen rise in CO₂.

Marsh gas raises temperature even more than than CO₂, and the amount of marsh gas in the atmosphere, like that of CO₂, is also at a level not seen in 800 millennia. Two thirds of current emissions of methane are past-products of human activeness, things similar the product of oil and natural gas, deforestation, decomposition of garbage and sewage, and raising farm animals.

Many people find information technology difficult to believe that human activeness can affect a arrangement as large as Earth'due south climate. After all, we are so tiny compared to the planet. But every day nosotros tiny human being beings drive cars; watch idiot box; plough on lamps; rut or cool our houses and offices; eat food transported to us by planes, ships, and trucks; clear or fire forests; and behave in endless other ways that straight or indirectly release greenhouse gases into the air. Together, we humans emitted 8 billion metric tons of carbon to our planet's temper in 2007 alone (Boden, Marland, & Andres, 2009). (CO_two weighs iii.66 times more than carbon; that ways we released 29.3 billion metric tons of CO_two.) The evidence is overwhelming that human activeness is responsible for the rise in CO_ii, methane, and other greenhouse gas levels, and that the increment in these gases is fueling the rise in hateful global temperature.

A global temperature rise of a few degrees may not seem such a bad thing, especially to people living in harsh, cold climates. But global warming does non mean only that nosotros will trade parkas for T-shirts or plow upward the air conditioning. A warming planet is a irresolute planet, and the changes will have profound consequences for all species that live on it, including humans. Those changes are non just something our children and grandchildren will have to bargain with in the future; they are taking identify now, and are affecting millions of people.

EFFECTS OF GLOBAL WARMING

One effect of global warming that everyone has heard about is a rise in sea levels. About half of this ascent is due to thermal expansion: Ocean temperatures are rising, and as h2o warms it expands. Put a nearly full cup of h2o in a microwave and heat it, and the water will spill over the cup.

In addition to thermal expansion, the oceans are rising because ice is melting, and most of that h2o inevitably finds its manner to the sea. So far, most of that water has come from mount glaciers and ice caps (Meier et al., 2007). As global temperatures increase, sea level rise will mainly reflect polar ice melt. Then far, ocean ascent has been measured in millimeters, only in that location is enough water in the Greenland ice sheet alone to raise bounding main levels by about 7 thousand, Westward Antarctica over v m, and Due east Antarctica nigh l m (Lemke et al., 2007). If the Globe were to lose just 8% of its water ice, the consequences for some coastal regions would be dramatic. The lower part of the Florida peninsula and much of Louisiana, including New Orleans, would be submerged, and low-lying cities, including London, New York, and Shanghai, would be endangered (to meet the effects of various magnitudes of sea level ascent in the San Francisco Bay surface area, get to http://cascade.wr.usgs.gov/data/Task2b-SFBay/data.shtm).

Low-lying continental countries such as the Netherlands and much of Bangladesh already find themselves battling flooding more than ever earlier. Many small island nations in the western Pacific (e.g., Vanuatu) are facing imminent destruction equally they are gradually overrun by the ascent body of water. Indonesia is an isle nation, and many of its 17,000 islands are only in a higher place sea level. At the 2007 Un Climate change Briefing in Bali, Indonesian environmental government minister Rachmat Witoelar stated that 2,000 of his state'south islands could be lost to sea level rise by 2030. At current rates of sea level rise, another isle nation, the Republic of Maldives, volition become uninhabitable by the cease of the century (http://unfcc.int/resources/docs/napa/mdv01.pdf). In 2008, the president of that country, Mohamed Nasheed, announced that he was contemplating moving his people to India, Sri Lanka, and Australia (Schmidle, 2009). One of the major effects of continued sea level rise volition be the displacement of millions of people. Where millions of climate refugees will find welcome is unclear. The migration of large numbers of people to new territories with unlike languages and cultures volition be disruptive, to say the least.

In improver to the danger of inundation, rising body of water levels bring salt water into rivers, spoil drinking wells, and turn fertile farmland into useless fields of salty soil. These effects of global warming are occurring now in places like the lowlands of People's republic of bangladesh (Church et al., 2001).

People on dry out country need the fresh water that is running into the sea. In the jump, melting water ice from mountain glaciers, water ice caps, and snowfields furnish wells and rivers that provide fresh water for drinking, agriculture, and hydroelectric power. For instance, in the dry season, people in large areas of Bharat, Nepal, and southern China depend on rivers fed past Himalayan glaciers. The retreat of these glaciers threatens the water supply of millions of people in this part of the world. Peru relies on hydroelectric power for eighty% of its free energy (Vergara et al., 2007), a pregnant portion of which comes from mount streams that are fed by mountain glaciers and ice fields. In Tanzania, the loss of Mount Kilimanjaro's fabled ice cover would probable accept a negative impact on tourism, which is the country'south primary source of foreign currency. The glaciers and snow packs in the Rocky Mountains are essential for farming in California, one of the world's most productive agronomical areas.

Global warming is expanding barren areas of the Globe. Warming at the equator drives a climate system chosen the Hadley Cell. Warm, moist air rises from the equator, loses its wet through rainfall, moves north and south, and so falls to the Earth at 30° north and s latitude, creating deserts and barren regions. At that place is evidence that over the last 20 years the Hadley Cell has expanded due north and south by most ii° breadth, which may broaden the desert zones (Seidel, Fu, Randel, & Reichler, 2008; Seidel & Randel, 2007). If and so, droughts may become more persistent in the American Southwest, the Mediterranean, Australia, South America, and Africa.

Global warming can also have effects that seem paradoxical. Continued warming may alter ocean currents that now bring warm water to the North Atlantic region, giving it a temperate climate. If this happens, Europe could experience a cooling even every bit other areas of the globe become warmer.

Accelerating Change

Information technology is hard to assess the full effects of global warming, and harder still to predict hereafter effects. Climate predictions are made with computer models, only these models have assumed a dull, steady charge per unit of change. Our best models predict a temperature rise in this century of between two.4° and 4.v° C (4.3° and 8.ane° F), with an boilerplate of almost 3° C (v.4° F; Meehl et al., 2007; Figure 1). But these models assume a linear rise in temperature. Increasingly, calculator models accept underestimated the trends because, in fact, the rate of global temperature rise is accelerating. The average rise in global temperature was 0.11° F per decade over the terminal century (National Oceanic and Atmospheric Assistants, 2009). Since the belatedly 1970s, however, this rate has increased to 0.29° F per decade, and 11 of the warmest years on record accept occurred in the last 12 years. May, 2010, was the 303rd sequent calendar month with a global temperature warmer than its 20th-century boilerplate (National Oceanic and Atmospheric Administration, 2010).

The dispatch of global temperature is reflected in increases in the rate of ice melt. From 1963 to 1978, the charge per unit of water ice loss on Quelccaya was about 6 yard per twelvemonth. From 1991 to 2006, information technology averaged 60 m per year, 10 times faster than the initial rate (Thompson et al., 2006). A recent paper by Matsuo and Heki (2010) reports uneven water ice loss from the loftier Asian ice fields, every bit measured by the Gravity Recovery and Climate Experiment satellite observations between 2003 and 2009. Water ice retreat in the Himalayas slowed slightly during this catamenia, and loss in the mountains to the northwest increased markedly over the concluding few years. Nevertheless, the average charge per unit of ice melt in the region was twice the rate of iv decades before. In the last decade, many of the glaciers that bleed Greenland and Antarctica have accelerated their belch into the world's oceans from twenty% to 100% (Lemke et al., 2007).

Increasing rates of ice cook should mean an increasing rate of ocean level ascent, and this is in fact the instance. Over most of the 20th century, sea level rose virtually 2 mm per year. Since 1990, the charge per unit has been near 3 mm per year.

And then, not just is Earth's temperature rising, merely the rate of this change is accelerating. This means that our future may not be a steady, gradual change in the earth's climate, simply an abrupt and devastating deterioration from which we cannot recover.

Abrupt Climate Change Possible

We know that very rapid alter in climate is possible because information technology has occurred in the past. One of the most remarkable examples was a sudden common cold, wet event that occurred virtually 5,200 years ago, and left its mark in many paleoclimate records effectually the world.

The most famous evidence of this abrupt weather modify comes from Otzi, the "Tyrolean ice man" whose remarkably preserved body was discovered in the Eastern Alps in 1991 later on information technology was exposed by a melting glacier. Forensic evidence suggests that Otzi was shot in the back with an arrow, escaped his enemies, so sat downward backside a boulder and bled to death. Nosotros know that inside days of Otzi'due south dying there must have been a climate outcome large plenty to entomb him in snow; otherwise, his trunk would have decayed or been eaten by scavengers. Radiocarbon dating of Otzi's remains revealed that he died effectually 5,200 years ago (Baroni & Orombelli, 1996).

The event that preserved Otzi could have been local, but other testify points to a global upshot of abrupt cooling. Around the world organic material is being exposed for the first time in five,200 years equally glaciers recede. In 2002, when we studied the Quelccaya water ice cap in southern Peru, we plant a perfectly preserved wetland establish. It was identified as Distichia muscoides, which today grows in the valleys beneath the water ice cap. Our specimen was radiocarbon dated at 5,200 years earlier present (Thompson et al., 2006). Every bit the glacier continues to retreat, more than plants have been collected and radiocarbon dated, nigh all of which confirm the original findings (Buffen, Thompson, Mosley-Thompson, & Huh, 2009).

Another record of this event comes from the ice fields on Mount Kilimanjaro. The ice dating back 5,200 years shows a very intense, very sudden decrease in the concentration of heavy oxygen atoms, or isotopes, in the water molecules that etch the water ice (Thompson et al., 2002). Such a decrease is indicative of colder temperatures, more intense snow, or both.

The Soreq Cave in Israel contains speleothems that accept produced continuous climate records spanning tens of thousands of years. The record shows that an abrupt cooling as well occurred in the Centre East about five,200 years agone, and that it was the most extreme climatic result in the concluding 13,000 years (Bar-Matthews, Ayalon, Kaufman, & Wasserburg, 1999).

One fashion that rapid climate change can occur is through positive feedback. In the physical sciences, positive feedback means that an event has an result which, in turn, produces more of the initial result. The best way to understand this miracle as information technology relates to climatic change is through some very plausible examples:

Higher global temperatures mean dryer forests in some areas, which means more woods fires, which ways more CO₂ and ash in the air, which raises global temperature, which ways more than forest fires, which means …

Higher global temperatures hateful melting ice, which exposes darker areas (dirt, rock, water) that reflect less solar energy than water ice, which ways college global temperatures, which means more melting ice, which means …

College global temperatures mean tundra permafrost melts, releasing CO_two and methane from rotted organic material, which means college global temperature, which ways more permafrost melting, which means …

Positive feedback increases the rate of alter. Somewhen a tipping point may be reached, after which it could be impossible to restore normal weather. Recollect of a very big boulder rolling down a colina: When information technology first starts to movement, we might finish information technology by pushing against it or wedging chocks under information technology or building a bulwark, but one time it has reached a certain velocity, at that place is no stopping it. Nosotros do not know if there is a tipping point for global warming, merely the possibility cannot be dismissed, and it has ominous implications. Global warming is a very, very large boulder.

Fifty-fifty if there is no tipping betoken (or nosotros manage to avoid it), the acceleration of warming means serious trouble. In fact, if we stopped emitting greenhouse gases into the atmosphere tomorrow, temperatures would continue to ascension for 20 to xxx years considering of what is already in the atmosphere. In one case methane is injected into the troposphere, it remains for near viii to 12 years (Prinn et al., 1987). Carbon dioxide has a much longer residence: lxx to 120 years. 20 percent of the CO₂ being emitted today will still affect the earth's climate one,000 years from now (Archer & Brovkin, 2008).

If, as predicted, global temperature rises another 3° C (5.4° F) by the terminate of the century, the globe will be warmer than it has been in nearly 3 million years (Dowsett et al., 1994; Rahmstorf, 2007). Oceans were then most 25 g college than they are today. We are already seeing important effects from global warming; the furnishings of some other three° C (5.four° F) increase are hard to predict. However, such a desperate change would, at the very to the lowest degree, put severe pressure on civilization as we know it.

OUR OPTIONS

Global warming is here and is already affecting our climate, so prevention is no longer an option. Three options remain for dealing with the crisis: mitigate, accommodate, and suffer.

Mitigation is proactive, and in the case of anthropogenic climate change it involves doing things to reduce the pace and magnitude of the changes by altering the underlying causes. The obvious, and almost hotly debated, remedies include those that reduce the volume of greenhouse gas emissions, especially CO₂ and methane. Examples include not but using compact fluorescent lightbulbs, adding insulation to our homes, and driving less, but societal changes such as shutting downward coal-fired power plants, establishing a federal carbon revenue enhancement (as was recently recommended past the National Academy of Sciences), and essentially raising minimum mileage standards on cars (National Enquiry Council, 2010). Another arroyo to mitigation that has received widespread attending recently is to enhance the natural carbon sinks (storage systems) through expansion of forests. Some have suggested various geo-engineering procedures (e.grand., Govindasamy & Caldeira, 2000; Wigley, 2006). One case is burying carbon in the ocean or under land surfaces (Brewer, Friederich, Peltzer, & Orr, 1999). Geo-applied science ideas are intriguing, merely some are considered radical and may lead to unintended negative consequences (Parkinson, 2010).

Adaptation is reactive. It involves reducing the potential adverse impacts resulting from the by-products of climate change. This might include constructing sea barriers such as dikes and tidal barriers (similar to those on the Thames River in London and in New Orleans), relocating coastal towns and cities inland, changing agricultural practices to counteract shifting atmospheric condition patterns, and strengthening human and fauna amnesty to climate-related diseases.

Our third option, suffering, means indelible the adverse impacts that cannot be staved off by mitigation or adaptation. Everyone will be affected past global warming, but those with the fewest resources for adapting will suffer most. It is a cruel irony that and so many of these people live in or well-nigh ecologically sensitive areas, such as grasslands (Outer Mongolia), dry lands (Sudan and Federal democratic republic of ethiopia), mountain glaciers (the Quechua of the Peruvian Andes), and coastal lowlands (Bangledesh and the Due south Sea isle region). Humans will not be the only species to suffer.

Conspicuously mitigation is our all-time option, but so far nigh societies effectually the world, including the United States and the other largest emitters of greenhouse gases, take done lilliputian more than than talk virtually the importance of mitigation. Many Americans do not fifty-fifty accept the reality of global warming. The fossil fuel manufacture has spent millions of dollars on a disinformation campaign to delude the public near the threat, and the entrada has been amazingly successful. (This effort is reminiscent of the tobacco industry's endeavour to convince Americans that smoking poses no serious health hazards.) Equally the evidence for human-acquired climate change has increased, the number of Americans who believe it has decreased. The latest Pew Research Center (2010) poll in October, 2009, shows that only 57% of Americans believe global warming is real, downwardly from 71% in Apr, 2008.

In that location are currently no technological quick fixes for global warming. Our merely hope is to change our behavior in ways that significantly tedious the rate of global warming, thereby giving the engineers time to devise, develop, and deploy technological solutions where possible. Unless large numbers of people have advisable steps, including supporting governmental regulations aimed at reducing greenhouse gas emissions, our only options volition be accommodation and suffering. And the longer nosotros filibuster, the more than unpleasant the adaptations and the greater the suffering volition be.

Sooner or later, nosotros will all deal with global warming. The merely question is how much nosotros will mitigate, adapt, and suffer.

Acknowledgments

This paper is based on the Presidential Scholar's Address given at the 35th annual coming together of the Clan for Behavior Analysis International, Phoenix, Arizona. I am grateful to Pecker Heward for inviting me to give the address. I give thanks Mary Davis for her help editing the text and figures. I wish to give thanks all the field and laboratory team members from the Byrd Polar Research Center who have worked and then diligently over the years. I am peculiarly indebted to the hard work of our current research team: Ellen Mosley-Thompson, Henry Brecher, Mary Davis, Paolo Gabrielli, Ping-Nan Lin, Matt Makou, Victor Zagorodnov, and all of our graduate students. Funding for our research over the years has been provided by the National Science Foundation's Paleoclimate Program, the National Oceanic and Atmospheric Administration'due south Paleoclimatology and Polar Programs, the National Aeronautic and Space Administration, Gary Comer Foundation, and The Ohio Country University's Climate, Water and Carbon Plan. This is Byrd Polar Research Heart Publication 1402.

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Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2995507/

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