Citerank: (12) 5202Earth's globally averaged surface temperature is risingObserved increases in the Earth's globally averaged surface temperature offer credible evidence of significant climate change.1198CE71, 5203Observed increases in global average ocean temperatureObserved increases in global average ocean temperature [citation needed].1198CE71, 5204Observed melting of snow and iceObservations of widespread melting of snow and ice.1198CE71, 5205Observed rises in global average sea levelThe rate of sea level rise since the mid-19th century has been larger than the mean rate during the previous two millennia (high confidence). Over the period 1901–2010, global mean sea level rose by 0.19 [0.17 to 0.21] m1198CE71, 39977Global CO2 emissions from fossil fuels 40% higher in 2008 than 1990Global carbon dioxide emissions from fossil fuels in 2008 were nearly 40% higher than those in 1990.1198CE71, 287960Warming of the climate system is unequivocalWarming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia. The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, sea level has risen, and the concentrations of greenhouse gases have increased.
959C6EF, 287961Observed changes in the climate systemWarming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia. The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, sea level has risen, and the concentrations of greenhouse gases have increased.1198CE71, 287962Observed changes in the atmosphereEach of the last three decades has been successively warmer at the Earth’s surface than any preceding decade since 1850. In the Northern Hemisphere, 1983–2012 was likely the warmest 30-year period of the last 1400 years (medium confidence).1198CE71, 287963Ocean warmingOcean warming dominates the increase in energy stored in the climate system, accounting for more than 90% of the energy accumulated between 1971 and 2010 (high confidence). It is virtually certain that the upper ocean (0-700 m) warmed from 1971 to 2010 and it likely warmed between the 1870s and 1971.1198CE71, 287964Observed cryospheric changesOver the last two decades, the Greenland and Antarctic ice sheets have been losing mass, glaciers have continued to shrink almost worldwide, and Arctic sea ice and Northern Hemisphere spring snow cover have continued to decrease in extent (high confidence).1198CE71, 287965Observed sea level changesThe rate of sea level rise since the mid-19th century has been larger than the mean rate during the previous two millennia (high confidence). Over the period 1901–2010, global mean sea level rose by 0.19 [0.17 to 0.21] m.1198CE71, 287966Observed changes in carbon and other biogeochemical cyclesThe atmospheric concentrations of carbon dioxide (CO2), methane, and nitrous oxide have increased to levels unprecedented in at least the last 800,000 years. CO2 concentrations have increased by 40% since pre-industrial times, primarily from fossil fuel emissions and secondarily from net land use change emissions. The ocean has absorbed about 30% of the emitted anthropogenic carbon dioxide, causing ocean acidification.1198CE71

Human influence has been detected in warming of the atmosphere and the ocean, in changes in the global water cycle, in reductions in snow and ice, in global mean sea level rise, and in changes in some climate extremes. This evidence for human influence has grown since AR4. It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century.

It is extremely likely [95–100%] that more than half of the observed increase in global average surface temperature from 1951 to 2010 was caused by the anthropogenic increase in greenhouse gas concentrations and other anthropogenic forcings together.

Human influence on the climate system... is evident from the increasing greenhouse gas concentrations in the atmosphere, positive radiative forcing, observed warming, and understanding of the climate system.