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Evidence

Evidence
The Earth's climate has changed throughout history. Just in the last 650,000 years there have been seven cycles of glacial advance and retreat, with the abrupt end of the last ice age about 7,000 years ago marking the beginning of the modern climate era — and of human civilization. Most of these climate changes are attributed to very small variations in Earth’s orbit that change the amount of solar energy our planet receives. Scientific evidence for warming of the climate system is unequivocal. The current warming trend is of particular significance because most of it is very likely human-induced and proceeding at a rate that is unprecedented in the past 1,300 years.1 Earth-orbiting satellites and other technological advances have enabled scientists to see the big picture, collecting many different types of information about our planet and its climate on a global scale. The evidence for rapid climate change is compelling: Sea level rise Global temperature rise Warming oceans Glacial retreat

http://climate.nasa.gov/evidence/

Related:  The Climate CrisisClimate CHANGEPhysical evidenceClimate ChangeClimate Change

Two degrees: Will we avoid dangerous climate change? 09 Dec 2014, 11:30Simon Evans Limiting warming to no more than two degrees has become the internationally accepted target for climate policy, as we saw in the first blog of our series of pieces looking at the two degrees limit. Scientists think the risks of climate change increase as temperatures rise. 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]

Understanding the Link Between Climate Change and Extreme Weather On This Page: Changes in Extreme Weather and Climate Events Scientists study many aspects of change in extreme weather and climate events. These include: Frequency: Are events occurring more often than they did in the past? Intensity: Are events getting more severe, with the potential for more damaging effects? Climate change What causes climate change? Just as the world’s most respected scientific bodies have confirmed that the Earth is getting hotter, they have also stated that there is strong evidence that humans are driving the warming (2). Scientists agree the main cause of climate change is human activities which magnify the ‘greenhouse effect’ – a natural process in which gases in the atmosphere warm the Earth by trapping heat that is radiating towards space (2) (4).

Oil Investors at Brink of Losing Trillions of Dollars in Assets. Gore: It's That Road Runner Moment Climate: Now or Never A major threat to fossil fuel companies has suddenly moved from the fringe to center stage with a dramatic announcement by Germany’s biggest power company and an intriguing letter from the Bank of England. A growing minority of investors and regulators are probing the possibility that untapped deposits of oil, gas and coal -- valued at trillions of dollars globally -- could become stranded assets as governments adopt stricter climate change policies. Ocean acidification NOAA provides evidence for upwelling of corrosive "acidified" water onto the Continental Shelf. 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. George, California.

CO2 sinks - Oceans Carbon dioxide readily dissolves in water and the oceans provide a huge reservoir of carbon. Across the world's oceans there is a continual cycle of equilibration of dissolved carbon dioxide in water with carbon dioxide in the atmosphere. Around 88 thousand million tonnes of carbon is released from the surface of the world's oceans each year, with an annual uptake by the oceans of 90 thousand million tonnes. Consequently, the net uptake of carbon dioxide by oceans is estimated to be approximately 2 thousand million tonnes annually. National Centers for Environmental Information (NCEI) IntroductionWarming ClimateHuman InfluenceMore Information Introduction Many lines of scientific evidence show the Earth's climate is changing. This page presents the latest information from several independent measures of observed climate change that illustrate an overwhelmingly compelling story of a planet that is undergoing global warming. It is worth noting that increasing global temperature is only one element of observed global climate change. Precipitation patterns are also changing; storms and other extremes are changing as well.

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. 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.

Giant iceberg poised to break off from Antarctic shelf A giant iceberg, with an area equivalent to Trinidad and Tobago, is poised to break off from the Antarctic shelf. A thread of just 20km of ice is now preventing the 5,000 sq km mass from floating away, following the sudden expansion last month of a rift that has been steadily growing for more than a decade. The iceberg, which is positioned on the most northern major ice shelf in Antarctica, known as Larsen C, is predicted to be one of the largest 10 break-offs ever recorded. Professor Adrian Luckman, a scientist at Swansea University and leader of the UK’s Midas project, said in a statement: “After a few months of steady, incremental advance since the last event, the rift grew suddenly by a further 18km during the second half of December 2016. Only a final 20km of ice now connects an iceberg one quarter the size of Wales to its parent ice shelf.” “If it doesn’t go in the next few months, I’ll be amazed,” Luckman told BBC News.

The climate crisis is already here – but no one’s telling us What is salient is not important. What is important is not salient. The media turns us away from the issues that will determine the course of our lives, and towards topics of brain-melting irrelevance. This, on current trends, will be the hottest year ever measured. Carbon bubble According to the UK MP Committee overvaluing companies that produce fossil fuels and greenhouse gases poses a serious threat to the economy. The UK MPs Committee warned British government and Bank of England of the risks of the carbon bubble in 2014.[1] Value[edit] Author Bill McKibben has estimated that to achieve human life to continue in the world up to $20tn worth of fossil fuel reserves will need to remain in the ground, essentially worthless.[2] British Stern report in 2006 stated that the benefits of strong, early action to decrase the use of oil, coal and gas considerably outweigh the costs. Fossil energy contributors, building industry and land use responsible ignore the responsibility in the external costs and ignore the Polluter pays principle according which the climate change costs will be paid by historical climate gas producers. History[edit]

Two degrees? Sounds nice. The reality will be rather different If we continue to emit ever-greater quantities of CO2 and other greenhouse gases into the atmosphere, then average global temperatures will rise by 2°C over the next three decades compared to pre-industrial times. Most scientists agree that anything higher is dangerous, though many argue that even this is too much. As the battles to reach an agreement in Paris begin, and with so much at stake, it is perhaps curious that few people really understand what a 2°C rise in average temperatures will mean.

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. The maps above show temperature anomalies, or changes, for 2000-2009 (top) and 1970-1979. The maps do not depict absolute temperature, but how much warmer or colder a region is compared to the norm for that same region from 1951-1980.

Related:  Climate Change