![]() ![]() In the Roman Warming, grapes and citrus were grown as far north as Hadrian’s Wall. The temperature and rate of temperature change in the Minoan, Roman and Medieval Warmings were greater than today. Some 6,000 years ago sea level was 2 metres higher than at present and it was at least 3✬ warmer than now.Ĭool times led to desertification and the collapse of great civilisations and warm times led to the thriving of humans. There were also alternating cool windy dry times and warm wet times. During the current interglacial, sea level has risen 130 metres in 14,000 years, a rate far higher than the most exaggerated model for human-induced global warming.ĭuring the current interglacial, there were a number of exceptionally cold snaps and temperature rose by as much as 20✬ in 15 years after one of these periods. The zenith of the last glaciation was 18,000 years ago. During the latest glaciation, the Toba supervolcano eruption 74,000 years ago led to intense cooling. The ice sheets did not completely melt and humans thrived. ![]() Ice core studies show that after a cyclical temperature increase, the atmospheric carbon dioxide content increased some 800 years later, again showing a disconnect between atmospheric temperature and carbon dioxide.ĭuring the last great interglacial some 125,000 years ago, sea level was 7 metres higher than at present and atmospheric temperature was some 5✬ warmer. These polar ice sheets waxed and waned, as they do now. It was only after two coincidental events 2.67 million years ago, the joining of the Americas and a supernoval eruption, that polar ice appeared in the Northern Hemisphere. Despite numerous long events when it was far warmer than at present, the Antarctic ice sheet did not melt. Because South America separated from Antarctica some 37 million years ago, the circum-polar current resulted in the isolation of Antarctica and the development of an ice sheet. There has been global cooling for the last 50 million years. In a past great ice age, an interglacial sea level rise of at least 600 metres was associated with a sea surface temperature rise to at least 40✬. The proposition that a high atmospheric carbon dioxide content creates global warming, tipping points and unstoppable global warming is incommensurate with the past. There have been six major ice ages.Two of these show that there was ice at sea level at the equator and five of these occurred when the carbon dioxide content of the atmosphere was up to 1,000 times greater than now. Pollution kills, carbon dioxide leads to the thriving of life on Earth and increased biodiversity. To state in public that carbon dioxide is a pollutant is a public advertisement of a lack of basic school child science. As a result, the atmospheric carbon dioxide has been decreasing over time despite massive additions from natural processes. During these times of very high atmospheric carbon dioxide, the oceans were not acid. Over the last 500 million years, carbon dioxide from the atmosphere has been sequestered into algal and coral reefs, shells, cements, precipitates, fossil fuels and sediments. Since the first photosynthetic bacteria on Earth more than 2,500 million years ago, life has been sequestering carbon dioxide. The greatest biomass on Earth has always been bacteria and bacteria are the only life on Earth that has ever made great changes to the atmosphere. In the past climate has not been driven by atmospheric carbon dioxide and water vapour is the main greenhouse gas. Random events, such as volcanoes, also changed climate. Past great climate changes were driven by natural cyclical processes such as the position of our Solar System in the Universe, wobbles in the Earth’s orbit, changes in the Sun, oscillations in the oceans and tidal changes. We humans have adapted to live on ice, mountains, in the tropics, in deserts and at sea level. Past temperate changes have been far greater and far more rapid than anything measured in modern times. For more than 80% of time, Earth has been an iceless, warm, wet, greenhouse planet.
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