International. 2017 was the third warmest year on record in the world, after 2016 (first) and 2015, according to the 28th annual State of the Climate report. The planet also experienced record concentrations of greenhouse gases, as well as sea level rises.
A graph showing the increasing number of hot days each year since 1950 relative to the 1961-1990 baseline, according to the State of the Climate in 2017 report published Aug. 1, 2018, in the Bulletin of the American Meteorological Society. "Hot days" are defined as the top 10% of high daytime temperatures during the reference period.
The annual global health check, led by scientists at NOAA's National Centers for Environmental Information and published by the Bulletin of the American Meteorological Society, is based on contributions from more than 500 scientists in 65 countries and provides information on global climate indicators. extreme weather events and other valuable environmental data.
Notable findings from the international report include:
Greenhouse gas levels were the highest on record. Major concentrations of greenhouse gases in the atmosphere, including carbon dioxide (CO2), methane and nitrous oxide, hit new records. The global average concentration of CO2 in 2017 was 405 parts per million, the highest measured in the current 38-year global climate record and records created from ice core samples dating back up to 800,000 years.
Sea level rise reached a new high: about 3 inches (7.7 cm) more than the 1993 average. Global sea level is rising at an average rate of 1.2 inches (3.1 cm) per decade.
The combined global land and ocean surface temperature reached an almost record high. Depending on the dataset, average global surface temperatures were 0.68-0.86 degrees F (0.38-0.48 degrees C) above the 1981-2010 average. This marks 2017 as the second or third warmest global temperature since records began in the mid to late 1800s.
Sea surface temperatures reach an almost record high. Although the global average sea surface temperature in 2017 was slightly lower than the value of 2016, the long-term trend remained upward.
The drought went down and then rebounded. The global drought area fell sharply in early 2017 before rising to above-average values later in the year.
Maximum Arctic sea ice cover fell to an all-time low. The 2017 maximum extent (coverage) of Arctic sea ice was the lowest on record for 38 years. The September 2017 sea ice minimum was the eighth-lowest on record, 25 percent smaller than the long-term average.
Antarctica also recorded unprecedented sea ice coverage, which remained well below the 1981-2010 average. On March 1, 2017, sea ice extent shrank to 811,000 square miles (2.1 million square kilometers), the lowest daily value observed in the continuous satellite record that began in 1978.
Unprecedented coral reef bleaching continued for several years: a global coral bleaching event spanned from June 2014 to May 2017, resulting in an unprecedented impact on reefs. More than 95 percent of the coral in some affected areas of the reef died.
The total number of tropical cyclones was slightly above the overall average. There were 85 named tropical cyclones in 2017, slightly above the 1981-2010 average of 82 storms.
Source: National Oceanic and Atmospheric Administration.
