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Physical evidence

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Evidence for climatic change is taken from a variety of sources that can be used to reconstruct past climates. Reasonably complete global records of surface temperature are available beginning from the mid-late 19th century.

For earlier periods, most of the evidence is indirect—climatic changes are inferred from changes in proxies, indicators that reflect climate, such as vegetation, ice cores,[60] dendrochronology, sea level change, and glacial geology. There’s growing evidence that global warming is driving crazy winters. Visualization of a very wavy northern hemisphere jet stream.

There’s growing evidence that global warming is driving crazy winters

Credit: NASA. AMS confirms Climate Change and Man's Role. Weathercasters in the U.S. not only tend to not ever mention climate change, but the majority of them do not even believe it is human-caused, as an article I recently wrote shows.

AMS confirms Climate Change and Man's Role

However, that may change. Scientific opinion on climate change. Global mean land-ocean temperature change since 1880, relative to the 1951–1980 mean.

Scientific opinion on climate change

The black line is the annual mean and the red line is the 5-year running mean. The green bars show uncertainty estimates. Source: NASA GISS. Antarctic Ice. Climate Change, Deforestation, Biomes and Ocean Currents, Plankton, Endangered Species - Earth Web Site. Click for more detail Thermohaline Change Evidence is growing that the thermohaline current may be slowed or stopped by cold fresh water inputs to the Arctic and North Atlantic oceans.

Climate Change, Deforestation, Biomes and Ocean Currents, Plankton, Endangered Species - Earth Web Site

This could occur if global warming is sufficient to cause large scale melting of arctic sea ice and the Greenland ice sheet. Such a change in the current may be gradual (over centuries) or very rapid (over a few years). Either would cause planet wide changes in climate. This effect may be part of what starts and stops the ice ages. Ocean acidification. NOAA provides evidence for upwelling of corrosive "acidified" water onto the Continental Shelf.

Ocean acidification

In the figure above, note the vertical sections of (A) temperature, (B) aragonite saturation, (C) pH, (D) DIC, and (E) pCO2 on transect line 5 off Pt. St. Current sea level rise. Trends in global average absolute sea level, 1870–2008.[1] Changes in sea level since the end of the last glacial episode.

Current sea level rise is about 3 mm/year worldwide. According to the US National Oceanic and Atmospheric Administration (NOAA), "this is a significantly larger rate than the sea-level rise averaged over the last several thousand years", and the rate may be increasing.[2] This rise in sea levels around the world potentially affects human populations in coastal and island regions[3] and natural environments like marine ecosystems.[4] Between 1870 and 2004, global average sea levels rose 195 mm (7.7 in), 1.46 mm (0.057 in) per year.[5] From 1950 to 2009, measurements show an average annual rise in sea level of 1.7 ± 0.3 mm per year, with satellite data showing a rise of 3.3 ± 0.4 mm per year from 1993 to 2009,[6] a faster rate of increase than previously estimated.[7] It is unclear whether the increased rate reflects an increase in the underlying long-term trend.[8]

Climate Change, Deforestation, Biomes and Ocean Currents, Plankton, Endangered Species - Earth Web Site. Evidence. The Earth's climate has changed throughout history.

Evidence

Global Warming Mapped. The world is getting warmer. Whether the cause is human activity or natural variability, thermometer readings all around the world have risen steadily since the beginning of the Industrial Revolution. According to an ongoing temperature analysis conducted by scientists at NASA’s Goddard Institute for Space Studies (GISS), the average global temperature on Earth has increased by about 0.8°Celsius (1.4°Fahrenheit) since 1880. Two-thirds of the warming has occurred since 1975, at a rate of roughly 0.15-0.20°C per decade. Climate Change Research. April, May, and June 2014 is the warmest three-month period ever. New data released Monday shows humanity has just unlocked another achievement in the race to cook the planet: The last three months were collectively the warmest ever experienced since record-keeping began in the late 1800s.

April, May, and June 2014 is the warmest three-month period ever.

The Japan Meteorological Agency said June 2014 was the warmest June globally since at least 1891, when its dataset begins. This follows May 2014, which was the warmest May globally on record, which follows April 2014, which was the warmest April globally on record. Taken as a whole, the just-finished three-month period was about 0.68 degrees Celsius (1.22 degrees Fahrenheit) above the 20th-century average. That may not sound like much, but the added warmth has been enough to provide a nudge to a litany of weather and climate events worldwide. Image: Japan Meteorological Agency Also on Monday, NASA released its monthly global temperature numbers for June, with nearly identical results that were reached by a different method. What Are the Range of Possibilities for Sea Level Rise Projections? Ask a Scientist - July 2014 J.

What Are the Range of Possibilities for Sea Level Rise Projections?

McReynolds of Oceanside, CA, asks "Projections of future sea level rise a century from now seem to be continually increasing. Arctic sea ice melt: Truth and inevitable denial. Sharon Jacob After a summer of seasonal melting, on Sept. 17, 2014, Arctic sea ice extent* likely hit its minimum for the year.

Arctic sea ice melt: Truth and inevitable denial.

The official word is that it was measured at 5.02 million square kilometers (1.94 million square miles). There’s growing evidence that global warming is driving crazy winters. Visualization of a very wavy northern hemisphere jet stream.

There’s growing evidence that global warming is driving crazy winters

Credit: NASA It may be the timeliest -- and most troubling -- idea in climate science. Back in 2012, two researchers with a particular interest in the Arctic, Rutgers' Jennifer Francis and the University of Wisconsin-Madison's Stephen Vavrus, published a paper called "Evidence linking Arctic amplification to extreme weather in mid-latitudes. " Effects of global warming on oceans. Animated map exhibiting the world's oceanic waters. A continuous body of water encircling the Earth, the World Ocean is divided into a number of principal areas with relatively free interchange among them. Five oceanic divisions are usually reckoned: Pacific, Atlantic, Indian, Arctic, and Southern; the last two listed are sometimes consolidated into the first three.

Global mean land-ocean temperature change from 1880–2011, relative to the 1951–1980 mean. The black line is the annual mean and the red line is the 5-year running mean. The green bars show uncertainty estimates. Energy (heat) added to various parts of the climate system due to global warming. Global warming can affect sea levels, coastlines, ocean acidification, ocean currents, seawater, sea surface temperatures,[1] tides, the sea floor, weather, and trigger several changes in ocean bio-geochemistry; all of these affect the functioning of a society.[2] Sea level[edit] Coasts[edit]

Temperature record of the past 1000 years. Temperature measurements and proxies. Historical impacts of climate change. Climate has affected human life and civilization from the emergence of hominins to the present day. These historical impacts of climate change can improve human life and cause societies to flourish, or can be instrumental in civilization's societal collapse. Role in human evolution[edit] Changes in East African climate have been associated with the evolution of hominins. Researchers have proposed that the regional environment transitioned from humid jungle to more arid grasslands due to tectonic uplift[1] and changes in broader patterns of ocean and atmospheric circulation.[2] This environmental change is believed to have forced hominins to evolve for life in a savannah-type environment.

Historic and prehistoric societies[edit] The rise and fall of societies have often been linked to environmental factors.[7] Societal growth and urbanization[edit] Glaciers.

Arctic sea ice loss

Vegetation. Pollen analysis. Cloud cover and precipitation. Dendroclimatology. Variation of tree ring width translated into summer temperature anomalies for the past 7000 years, based on samples from holocene deposits on Yamal Peninsula and Siberian now living conifers.[1] Advantages[edit] Limitations[edit] Ice cores. Animals. Sea level change.