- Catastrophic Climate Change
- Asteroid Reports to Prevent an Extinction Level Event (National Geographic)
"The Minor Planet Center, a clearing house for asteroid observations, receives up to 15,000 new sightings a day from the LINEAR telescopes alone."
"The Center is part of a (U.S.) 3.5-million dollar-a-year NASA program, called Spaceguard, that locates asteroids in Earth's neighborhood. This program focuses on the estimated 1,200 to 1,500 larger asteroids in our area that are over 1 kilometer (0.6 mile) wide and could be potential planet killers, like the one that probably killed the dinosaurs some 65 million years ago."
- Averting an Asteroid Strike (Christian Science Monitor)
"Scientists and engineers who have studied the problem of deflecting a dangerous asteroid believe the technical issues are difficult but solvable. The challenge now is figuring out the legal issues of who takes action on behalf of humankind and of what their responsibilities and liabilities will be." 05-09
- Doomsday Clock (BBC News)
"Experts assessing the dangers posed to civilisation have added climate change to the prospect of nuclear annihilation as the greatest threats to humankind." 01-07
- Doomsday Vault (NewScientist.com)
"The room is a 'doomsday vault' designed to hold around 2 million seeds, representing all known varieties of the world's crops. It is being built to safeguard the world's food supply against nuclear war, climate change, terrorism, rising sea levels, earthquakes and the ensuing collapse of electricity supplies." 01-07
- Extinction Level Event (National Geographic)
"Scientists studying the fallout from a huge asteroid that crashed into Earth 65 million years ago have gained better understanding of the event that most likely took out the dinosaurs and much other life on the planet."
"The asteroid that created the Chicxulub (pronounced CHEEK-shoo-loob) crater, located on the Yucatán Peninsula of Mexico, was probably more than 6 miles (10 kilometers) wide, researchers estimate. The resulting crater was 110 to 125 miles (180 to 200 kilometers) wide and very deep. Today it is buried under several miles of limestone and is mostly underwater."
- Extinction Level Event (Wikipedia.org)
"An extinction event (also extinction-level event, ELE) occurs when a large number of species die out in a relatively short period of time. Based on the fossil record, the background rate of extinctions on Earth is about two to five taxonomic families of marine invertebrates and vertebrates every million years."
"The classical 'Big Five' mass extinctions identified by Raup and Sepkoski (1982) are widely agreed upon as some of the most significant: End Ordovician, Late Devonian, End Permian, End Triassic, and End Cretaceous." 03-06
- Extinction Level Event: End Permian (ScienceDaily.com)
"In the end-Permian, as the levels of atmospheric oxygen fell and the levels of hydrogen sulfide and carbon dioxide rose, the upper levels of the oceans could have become rich in hydrogen sulfide catastrophically. This would kill most of the oceanic plants and animals. The hydrogen sulfide dispersing in the atmosphere would kill most terrestrial life." 12-07
- Gamma-Ray Bursts (Wikipedia.org)
"Gamma-ray bursts (GRBs) are the most luminous events known in the universe since the Big Bang. They are flashes of gamma rays coming from seemingly random places in deep space at random times. GRBs last from milliseconds to many minutes, and are often followed by 'afterglow' emission at longer wavelengths (X-ray, UV, optical, IR, and radio). Gamma-ray bursts are detected by orbiting satellites about two to three times a week, as of 2007, though their actual rate of occurrence is much higher."
"One line of research has investigated the consequences of Earth being hit by a beam of gamma rays from a nearby (about 500 light years) gamma ray burst. This is motivated by the efforts to explain mass extinctions on Earth and estimate the probability of extraterrestrial life. The consensus seems to be that the damage that a gamma ray burst could do would be limited by its very short duration, and the fact that it would only cover half the Earth (the other half would be in its shadow). A sufficiently close gamma ray burst could do serious damage to atmospheric chemistry, perhaps instantly wiping out half the ozone layer, and causing nitrogen-oxygen recombination, generating acidic nitrogen oxides. These effects would diffuse across to the other side of the Earth and result in long-term climate and atmospheric changes, resulting in a mass extinction. The damage from a gamma ray burst would probably be significantly greater than a supernova at the same distance." 10-07
- Ten Signs We Might Be Experiencing a Mass Extinction (Animal.Discovery.com)
"Researchers have documented a fraction of the species on Earth, so how can we know — or even suspect — that we're in the middle of a mass extinction? Read on to learn about 10 of the biggest warning signs." 09-09
- Younger Dryas Period (Wikpedia.org)
"The Younger Dryas saw a rapid return to glacial conditions in the higher latitudes of the Northern Hemisphere between 12.9–11.5 ka BP in sharp contrast to the warming of the preceding interstadial deglaciation. It has been believed that the transitions each occurred over a period of a decade or so, but the onset may have been faster. Thermally fractionated nitrogen and argon isotope data from Greenland ice core GISP2 indicate that the summit of Greenland was approximately 15 °C (27.0 °F) colder during the Younger Dryas than today. In the UK, coleopteran fossil evidence (from beetles) suggests that mean annual temperature dropped to approximately 5 °C (41 °F), and periglacial conditions prevailed in lowland areas, while icefields and glaciers formed in upland areas. Nothing of the size, extent, or rapidity of this period of abrupt climate change has been experienced since."
In everyday language, around 12,900 years ago a catastrophic event caused a rapid climate change. 08-11
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