美国气象学会最新气候变化报告摘要- Climate Change-An Statement of the American Meteorological Society-Adopted by the AMS Council on 15-April-2019

Research has found a human influence on the climate of the past several decades. Its manifestation

includes the warming of the atmosphere and oceans, intensification of the heaviest precipitation over

continental areas, increasing upper-ocean acidity, increasing frequency and intensity of daily temperature

extremes, reductions in Northern Hemisphere snow and ice, and rising global sea level. The latitudinal

and seasonal observations of the surface warming and the observed warming of the troposphere and

cooling of the stratosphere are consistent with theoretical expectations from increased concentrations of

greenhouse gases.The increase in global average surface temperature over the past half-century cannot be fully explained

by natural climate variability, e.g., responses to Earth’s orbital changes over thousands of years, or natural climate forcing

such as from solar or volcanic variability. The observed warming rate varies from place to place and from decade to

decade because of natural climate variations, such as natural swings between El Niño and La Niña on time scales of two to

seven years, and variations in ocean circulation in the Pacific and Atlantic basins on decadal to multi-decadal timescales.

The influence of these relatively short-period fluctuations is factored into climate change analyses. These natural

fluctuations have neither the magnitude nor the spatial characteristics to explain the observed warming of Earth’s

average surface temperature over the past several decades.The IPCC (2013), USGCRP (2017), and USGCRP (2018) indicate

that it is extremely likely that human influence has been the dominant cause of the observed warming since the mid-

twentieth century.