Richard Alley | |
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Born | Richard Blane Alley 18 August 1957 |
Alma mater | |
Known for | |
Awards | ForMemRS [3] 2014 BBVA Foundation Frontiers of Knowledge Award Heinz Award with special focus on the Environment (2011) Roger Revelle Medal (2007) AGU Fellow (2000) [4] |
Scientific career | |
Institutions | Pennsylvania State University |
Thesis | Transformations in polar firn (1987) |
Doctoral advisor | Charles R. Bentley [5] |
Website | www |
Richard Blane Alley (born 18 August 1957) [6] is an American geologist and Evan Pugh Professor of Geosciences at Pennsylvania State University. [7] He has authored more than 240 refereed scientific publications about the relationships between Earth's cryosphere and global climate change, [5] and is recognized by the Institute for Scientific Information as a Highly Cited Researcher. [8] [9] [10] [11]
Alley was educated at Ohio State University and University of Wisconsin–Madison, where he was awarded a PhD in 1987. [12]
In 1999, Alley was invited to testify about climate change by Vice President Al Gore [13] after his research with Greenland ice cores indicated that the last Ice Age ended abruptly and violently rather than as a result of gradual change. [14] He appeared again before the U.S. Senate Committee on Commerce, Science, and Transportation in 2003; before the U.S. House Committee on Science and Technology in 2007; [15] and in 2010. [16] [17]
Alley's 2007 testimony was due to his role as a lead author of "Chapter 4: Observations: Changes in Snow, Ice and Frozen Ground" for the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC). He has participated in the joint UN/WMO panel since 1992, having been a contributing author to both the second and third IPCC assessment reports.
Alley has written several papers in the journals Nature and Science , [7] [18] [19] [20] [21] [22] and chaired the National Research Council on Abrupt Climate Change. In 2000, he published the book The Two-Mile Time Machine: Ice Cores, Abrupt Climate Change, and Our Future. He has appeared in numerous climate change-related television documentaries and has given many public presentations and media interviews about the subject. [23] [24] [25] [26]
Alley gave the Bjerknes lecture to the 2009 American Geophysical Union meeting titled "The biggest control knob- Carbon Dioxide in Earth's climate history". A video of the presentation [27] is available (also available on YouTube).
His more recent work has examined ice sheets and the factors that affect "calving", the process by which ice sheets break up. [14] [28]
Alley was awarded the Seligman Crystal in 2005 "for his prodigious contribution to our understanding of the stability of the ice sheets and glaciers of Antarctica and Greenland, and of erosion and sedimentation by this moving ice." [5] Alley is one of several Penn State earth scientists who are contributors to the United Nations Intergovernmental Panel on Climate Change, which shared the 2007 Nobel Peace Prize with Al Gore.
In 2005 he was also the first recipient of the Louis Agassiz Medal for his "outstanding and sustained contribution to glaciology and for his effective communication of important scientific issues in the public policy arena". [29] His award citation stated "He is imaginative, sharp and humorous, and remains a thorn in the backside of the Bush administration." [29]
In 2008 Alley was elected to the National Academy of Sciences. He was elected a Fellow of the American Academy of Arts and Sciences in 2010. [30]
In 2011, he received the 17th Annual Heinz Award with a special focus on the environment. [31] [32]
On 28 April 2014 the National Center for Science Education announced that its first annual Friend of the Planet award had been presented to Alley and Michael E. Mann. [33] He was elected a Foreign Member of the Royal Society (ForMemRS) in the same year, his nomination reads:
Richard Alley has made outstanding contributions to the study of ice, its interactions with the landscape and its link to climate. He has made important advances in topics as diverse as grain-scale physics controlling ice deformation, the role and nature of ice streams, and processes at the bed of the ice sheet. His work synthesised the evidence that abrupt climate changes occurred in the past, and drove hypotheses about their cause and the role of ice on ocean circulation. Alley is also an outstanding science communicator, whose skill and enthusiasm has influenced both policymakers and large public audiences. [3]
He won the 2014 BBVA Foundation Frontiers of Knowledge Award in Climate Change category for his “pioneering research” into the “mechanics of ice and its implications for abrupt climate change,” in the words of the jury's citation. He is the 2017 recipient of the Wollaston Medal, which is the highest award given by the Geological Society of London. It is reserved for geologists who have made a significant impact on the field through a substantial body of impactful research.
In 2018, Alley was named the recipient of the Roy Chapman Andrews Society Distinguished Explorer Award. [34] Alley was chosen primarily because of his discoveries advancing the understanding of rapid climate change and the stability of polar climates.
In addition to his research, Alley has made several appearances on television. On Sunday, April 10, 2011, PBS debuted a special program on climate change, entitled EARTH: The Operators’ Manual, [35] hosted by Alley. [36] The program's aim was to present an objective, accessible assessment of the Earth's problems and possible solutions, with the stated intention of leaving viewers informed, energized and optimistic. The series continued through 2012 on PBS and affiliates. The series is accompanied by a book of the same name, also by Richard Alley. [37] It was published on April 18, 2011. He has also appeared in episodes of the History Channel series Mega Disasters .[ citation needed ]
The Younger Dryas (YD) was a period in Earth's geologic history that occurred circa 12,900 to 11,700 years Before Present (BP). It is primarily known for the sudden or "abrupt" cooling in the Northern Hemisphere, when the North Atlantic Ocean cooled and annual air temperatures decreased by ~3 °C (5.4 °F) over North America, 2–6 °C (3.6–10.8 °F) in Europe and up to 10 °C (18 °F) in Greenland, in a few decades. Cooling in Greenland was particularly rapid, taking place over just 3 years or less. At the same time, the Southern Hemisphere had experienced warming. This period ended as rapidly as it began, with dramatic warming over ~50 years, which had transitioned the Earth from the glacial Pleistocene epoch into the current Holocene.
In glaciology, an ice sheet, also known as a continental glacier, is a mass of glacial ice that covers surrounding terrain and is greater than 50,000 km2 (19,000 sq mi). The only current ice sheets are the Antarctic ice sheet and the Greenland ice sheet. Ice sheets are bigger than ice shelves or alpine glaciers. Masses of ice covering less than 50,000 km2 are termed an ice cap. An ice cap will typically feed a series of glaciers around its periphery.
The Last Interglacial, also known as the Eemian among other names, was the interglacial period which began about 130,000 years ago at the end of the Penultimate Glacial Period and ended about 115,000 years ago at the beginning of the Last Glacial Period. It corresponds to Marine Isotope Stage 5e. It was the second-to-latest interglacial period of the current Ice Age, the most recent being the Holocene which extends to the present day. During the Last Interglacial, the proportion of CO2 in the atmosphere was about 280 parts per million. The Last Interglacial was one of the warmest periods of the last 800,000 years, with temperatures comparable to and at times warmer than the contemporary Holocene interglacial, with the maximum sea level being up to 6 to 9 metres higher than at present, with global ice volume likely also being smaller than the Holocene interglacial.
Dansgaard–Oeschger events, named after palaeoclimatologists Willi Dansgaard and Hans Oeschger, are rapid climate fluctuations that occurred 25 times during the last glacial period. Some scientists say that the events occur quasi-periodically with a recurrence time being a multiple of 1,470 years, but this is debated. The comparable climate cyclicity during the Holocene is referred to as Bond events.
The West Antarctic Ice Sheet (WAIS) is the segment of the continental ice sheet that covers West Antarctica, the portion of Antarctica on the side of the Transantarctic Mountains that lies in the Western Hemisphere. It is classified as a marine-based ice sheet, meaning that its bed lies well below sea level and its edges flow into floating ice shelves. The WAIS is bounded by the Ross Ice Shelf, the Ronne Ice Shelf, and outlet glaciers that drain into the Amundsen Sea.
The Greenland ice sheet is an ice sheet which forms the second largest body of ice in the world. It is an average of 1.67 km (1.0 mi) thick, and over 3 km (1.9 mi) thick at its maximum. It is almost 2,900 kilometres (1,800 mi) long in a north–south direction, with a maximum width of 1,100 kilometres (680 mi) at a latitude of 77°N, near its northern edge. The ice sheet covers 1,710,000 square kilometres (660,000 sq mi), around 80% of the surface of Greenland, or about 12% of the area of the Antarctic ice sheet. The term 'Greenland ice sheet' is often shortened to GIS or GrIS in scientific literature.
The global temperature record shows the fluctuations of the temperature of the atmosphere and the oceans through various spans of time. There are numerous estimates of temperatures since the end of the Pleistocene glaciation, particularly during the current Holocene epoch. Some temperature information is available through geologic evidence, going back millions of years. More recently, information from ice cores covers the period from 800,000 years before the present time until now. A study of the paleoclimate covers the time period from 12,000 years ago to the present. Tree rings and measurements from ice cores can give evidence about the global temperature from 1,000-2,000 years before the present until now. The most detailed information exists since 1850, when methodical thermometer-based records began. Modifications on the Stevenson-type screen were made for uniform instrument measurements around 1880.
The Greenland Ice Core Project (GRIP) was a research project organized through the European Science Foundation (ESF). The project ran from 1989 to 1995, with drilling seasons from 1990 to 1992. In 1988, the project was accepted as an ESF-associated program, and the fieldwork was started in Greenland in the summer of 1989.
An abrupt climate change occurs when the climate system is forced to transition at a rate that is determined by the climate system energy-balance. The transition rate is more rapid than the rate of change of the external forcing, though it may include sudden forcing events such as meteorite impacts. Abrupt climate change therefore is a variation beyond the variability of a climate. Past events include the end of the Carboniferous Rainforest Collapse, Younger Dryas, Dansgaard–Oeschger events, Heinrich events and possibly also the Paleocene–Eocene Thermal Maximum. The term is also used within the context of climate change to describe sudden climate change that is detectable over the time-scale of a human lifetime. Such a sudden climate change can be the result of feedback loops within the climate system or tipping points in the climate system.
This timeline lists events in the external environment that have influenced events in human history. This timeline is for use with the article on environmental determinism. For the history of humanity's influence on the environment, and humanity's perspective on this influence, see timeline of history of environmentalism. See List of periods and events in climate history for a timeline list focused on climate.
The Atlantic meridional overturning circulation (AMOC) is the main ocean current system in the Atlantic Ocean. It is a component of Earth's ocean circulation system and plays an important role in the climate system. The AMOC includes Atlantic currents at the surface and at great depths that are driven by changes in weather, temperature and salinity. Those currents comprise half of the global thermohaline circulation that includes the flow of major ocean currents, the other half being the Southern Ocean overturning circulation.
Radioglaciology is the study of glaciers, ice sheets, ice caps and icy moons using ice penetrating radar. It employs a geophysical method similar to ground-penetrating radar and typically operates at frequencies in the MF, HF, VHF and UHF portions of the radio spectrum. This technique is also commonly referred to as "Ice Penetrating Radar (IPR)" or "Radio Echo Sounding (RES)".
William Richard Peltier, Ph.D., D.Sc. (hc), is university professor of physics at the University of Toronto. He is director of the Centre for Global Change Science, past principal investigator of the Polar Climate Stability Network, and the scientific director of Canada's largest supercomputer centre, SciNet. He is a fellow of the Royal Society of Canada, of the American Geophysical Union, of the American Meteorological Society, and of the Norwegian Academy of Science and Letters..
In climatology, the 8.2-kiloyear event was a sudden decrease in global temperatures that occurred approximately 8,200 years before the present, or c. 6,200 BC, and which lasted for the next two to four centuries. It defines the start of the Northgrippian age in the Holocene epoch. The cooling was significantly less pronounced than during the Younger Dryas cold period that preceded the beginning of the Holocene. During the event, atmospheric methane concentration decreased by 80 ppb, an emission reduction of 15%, by cooling and drying at a hemispheric scale.
The WAIS Divide is the ice flow divide on the West Antarctic Ice Sheet (WAIS) which is a linear boundary that separates the region where the ice flows to the Ross Sea, from the region where the ice flows to the Weddell Sea. It is similar to a continental hydrographic divide.
The East Antarctic Ice Sheet (EAIS) lies between 45° west and 168° east longitudinally. It was first formed around 34 million years ago, and it is the largest ice sheet on the entire planet, with far greater volume than the Greenland ice sheet or the West Antarctic Ice Sheet (WAIS), from which it is separated by the Transantarctic Mountains. The ice sheet is around 2.2 km (1.4 mi) thick on average and is 4,897 m (16,066 ft) at its thickest point. It is also home to the geographic South Pole, South Magnetic Pole and the Amundsen–Scott South Pole Station.
In climate science, a tipping point is a critical threshold that, when crossed, leads to large, accelerating and often irreversible changes in the climate system. If tipping points are crossed, they are likely to have severe impacts on human society and may accelerate global warming. Tipping behavior is found across the climate system, for example in ice sheets, mountain glaciers, circulation patterns in the ocean, in ecosystems, and the atmosphere. Examples of tipping points include thawing permafrost, which will release methane, a powerful greenhouse gas, or melting ice sheets and glaciers reducing Earth's albedo, which would warm the planet faster. Thawing permafrost is a threat multiplier because it holds roughly twice as much carbon as the amount currently circulating in the atmosphere.
Siple Dome is an ice dome approximately 100 km wide and 100 km long, located 130 km east of Siple Coast in Antarctica. Charles Bentley and Robert Thomas established a "strain rosette" on this feature to determine ice movement in 1973–74. They referred to the feature as Siple Dome because of its proximity to Siple Coast.
The Mid-Pleistocene Transition (MPT), also known as the Mid-Pleistocene Revolution (MPR), is a fundamental change in the behaviour of glacial cycles during the Quaternary glaciations. The transition occurred gradually, taking place approximately 1.25–0.7 million years ago, in the Pleistocene epoch. Before the MPT, the glacial cycles were dominated by a 41,000-year periodicity with low-amplitude, thin ice sheets, and a linear relationship to the Milankovitch forcing from axial tilt. Because of this, sheets were more dynamic during the Early Pleistocene. After the MPT there have been strongly asymmetric cycles with long-duration cooling of the climate and build-up of thick ice sheets, followed by a fast change from extreme glacial conditions to a warm interglacial. This led to less dynamic ice sheets. Interglacials before the MPT had lower levels of atmospheric carbon dioxide compared to interglacials after the MPT. One of the MPT's effects was causing ice sheets to become higher in altitude and less slippery compared to before. The MPT greatly increased the reservoirs of hydrocarbons locked up as permafrost methane or methane clathrate during glacial intervals. This led to larger methane releases during deglaciations. The cycle lengths have varied, with an average length of approximately 100,000 years.
Bette Otto-Bliesner is an earth scientist known for her modeling of Earth's past climate and its changes over different geological eras.