Is another ice age predicted for the future?
295445#7
The idea that ice ages cycles were predictable appears to have become conflated with the idea that another one was due "soon" - perhaps because much of this study was done by geologists, who are accustomed to dealing with very long time scales and use "soon" to refer to periods of thousands of years. A strict application of the Milankovitch theory does not allow the prediction of a "rapid" ice age onset (i.e., less than a century or two) since the fastest orbital period is about 20,000 years. Some creative ways around this were found, notably one championed by Nigel Calder under the name of "snowblitz", but these ideas did not gain wide acceptance.
Global cooling
2321972#2
In the third edition of "The Encyclopedia of Science Fiction", author and critic John Clute writes of "Inter Ice Age 4": "It is a complex story set in a near-future Japan threatened by the melting polar ice caps. The protagonist, Professor Katsumi, has been in charge of developing a computer/information system capable of predicting human behavior. Fatally for him, this system predicts his compulsive refusal to go along with his associates and his government in the creation of genetically engineered children, adapted for life in the rising seas. Most of the novel, narrated by Katsumi, deals with a philosophical confrontation between his deeply alienated refusal of the future and the computer's knowing representations of that refusal and the alternatives to it. The resulting psychodramas include a mysterious murder and the enlistment of his unborn child into the ranks of the mutated water-breathers."
Inter Ice Age 4
2321972#1
Plot elements include submersion of the world caused by melting polar ice, genetic creation of gilled children for the coming underwater age, and a fortune-telling computer predicting the future and advising humans how to deal with it. Because a similar computer in Moscow is being used to make political forecasts, the institute of a Tokyo professor decides to avoid politics and try to foresee the future of an individual. A man is picked, apparently at random, only to be murdered before he can be programmed, but the computer can still read his mind. The resulting involvements are complicated by a climactic shift – Inter Ice Age 4 – which puts Earth underwater.
Inter Ice Age 4
24179592#13
Historically, there have been cyclical ice ages in which glacial sheets periodically covered the higher latitudes of the continents. Ice ages may occur because of changes in ocean circulation and continentality induced by plate tectonics. The Milankovitch theory predicts that glacial periods occur during ice ages because of astronomical factors in combination with climate feedback mechanisms. The primary astronomical drivers are a higher than normal orbital eccentricity, a low axial tilt (or obliquity), and the alignment of summer solstice with the aphelion. Each of these effects occur cyclically. For example, the eccentricity changes over time cycles of about 100,000 and 400,000 years, with the value ranging from less than 0.01 up to 0.05. This is equivalent to a change of the semiminor axis of the planet's orbit from 99.95% of the semimajor axis to 99.88%, respectively.
Future of Earth
40659364#7
Many scientists have attempted to estimate when the Arctic will be "ice-free". Professor Peter Wadhams of the University of Cambridge is among these scientists. Wadhams and several others have noted that climate model predictions have been overly conservative regarding sea ice decline. A 2013 paper suggested that models commonly underestimate the solar radiation absorption characteristics of wildfire soot. A 2006 paper predicted "near ice-free September conditions by 2040". Overland and Wang (2013) investigated three different ways of predicting future sea ice levels. From sea ice models and recent satellite images it can be expected that a sea ice free summer will come before 2020. The IPCC AR5 (for at least one scenario) estimates an ice-free summer might occur around 2050. The Third U.S. National Climate Assessment (NCA), released May 6, 2014, reports that the Arctic Ocean is expected to be ice free in summer before mid-century. Models that best match historical trends project a nearly ice-free Arctic in the summer by the 2030s. However, these models do tend to underestimate the rate of sea ice loss since 2007. Based on the outcomes of several different models, Overland and Wang (2013) put the early limit for a sea ice free summer Arctic near 2040.
Arctic sea ice decline
13294262#12
The Arctic ocean will likely be free of summer sea ice before the year 2100, but many different dates have been projected. One study suggests 2060–2080 and another suggests 2030. A 2013 study showed that simply extending summertime ice melting trends into the future in a straight line predicts an ice-free summertime Arctic as early as by 2020.
Climate change in the Arctic
15361#28
According to research published in "Nature Geoscience", human emissions of carbon dioxide (CO) will defer the next ice age. Researchers used data on Earth's orbit to find the historical warm interglacial period that looks most like the current one and from this have predicted that the next ice age would usually begin within 1,500 years. They go on to say that emissions have been so high that it will not.
Ice age
24179592#24
Christopher Scotese and his colleagues have mapped out the predicted motions several hundred million years into the future as part of the Paleomap Project. In their scenario, 50 million years from now the Mediterranean sea may vanish and the collision between Europe and Africa will create a long mountain range extending to the current location of the Persian Gulf. Australia will merge with Indonesia, and Baja California will slide northward along the coast. New subduction zones may appear off the eastern coast of North and South America, and mountain chains will form along those coastlines. To the south, the migration of Antarctica to the north will cause all of its ice sheets to melt. This, along with the melting of the Greenland ice sheets, will raise the average ocean level by . The inland flooding of the continents will result in climate changes.
Future of Earth
43334606#1
In 2011, Hill's research, which had used helioseismography to monitor streams below the surface of the sun, attracted considerable media attention. Although such streams tend to be the "spawning ground" for sunspots, and they had been expected to begin forming in 2008, the study found that these new streams had yet to form. The study in question therefore suggested that the sunspot cycle was going to take longer than expected to reach its next peak, or, according to Hill, might not happen at all. Although Hill and his colleagues refused to discuss the possible effects this weaker solar cycle would have on climate, this was reported on by some media, including the Global Warming Policy Foundation, as evidence that a "mini ice age" was imminent. Hill responded to these reports by telling Reuters that "We have not predicted a Little Ice Age," but rather that "We have predicted something going on with the Sun." In an NSO press release, Hill added that "In my opinion, it is a huge leap from that to an abrupt global cooling, since the connections between solar activity and climate are still very poorly understood. My understanding is that current calculations suggest only a 0.3 degree C decrease from a Maunder-like minimum, too small for an ice age."
Frank Hill (scientist)
372622#6
Croll's theory predicted multiple ice ages, asynchronous in northern and southern hemispheres, and that the last ice ages should have ended about 80,000 years ago. Evidence was just then emerging of multiple ice ages, and geologists were interested in a theory to explain this. Geologists were not then able to date sediments accurately enough to determine if glaciation was synchronous between the hemispheres, though the limited evidence more pointed towards synchronicity than not. More crucially, estimates of the recession rate of the Niagara Falls indicated that the last ice age ended 6,000 to 35,000 years ago – a large range, but enough to rule out Croll's theory, to those who accepted the measurements.
James Croll