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State of the Climate in 2018 – the fourth warmest year on record

Continued emissions of major greenhouse gases are a major factor in the global warming trend
Aug 12 2019

The 29th annual State of the Climate report, compiled by NOAA’s Center for Weather and Climate at the National Centers for Environmental Information and published today in the Bulletin of the American Meteorological Society, confirms that 2018 was the fourth warmest year on record, after 2016, 2015 and 2017.

The trends shown by the report's comprehensive analysis of a suite of global environmental observing instruments that track global and regional climate (on land, water, ice, in the atmosphere, and in space) are consistent with those of a warming planet.

The main findings of the report are that:

  • 2018 was one of the hottest years on record, and every year since the turn of the 21st century has been hotter than any of the past century;
  • The combined direct warming influence of greenhouse gases in the atmosphere is now nearly 43% stronger than in 1990;
  • Global carbon dioxide (CO2) concentrations reached a record 407.4 parts per million. The prevalence of other major greenhouse gases, such as methane and nitrous oxide, also increased in 2018;
  • As of 2018, the world’s glaciers have collectively lost mass 30 years in a row;
  • In March 2018, first-year ice (which is especially prone to summer melting) accounted for up to 77% of the ice cover, as compared to typically 55% during the spring peaks of the 1980s;
  • Global sea surface temperatures in 2018 were 0.33°C above the 1980–2010 average - not as hot as 2016, but enough to sustain the continued trend of 0.10°C increase per decade since 1950 and the acceleration of the trend in this century;
  • This heating extends to the depths: global ocean heat content from the surface down to 700 metres set a record again in 2018;
  • For the seventh year in a row, global annual mean sea level reached a record height as tracked in the 26 years of measurements using remote sensing by satellites.

The report is composed of six main chapters: Global Climate, Global Oceans, The Tropics, The Arctic, Antarctica and Regional Climates.

JRC scientist Nadine Gobron was co-author of the overview of the chapter on 'Global Climate'.

Global Climate Chapter

This chapter confirms that 2018 was the fourth warmest year since records began in the 1800s, and that every year of the 21st century has been warmer than the 1981-2010 global average.

In addition, there were more high temperature extremes in 2018 than in nearly all the previous 68 years on record, including prolonged heatwaves in North America, Europe, Australia and East Asia. Several unusually cold periods were also reported.

The annual temperature of most lakes continued to rise, especially in the northern mid-latitudes.

While the area of land subject to drought was below average, 20% suffered moderate or worse drought, with Afghanistan, regions of the Middle East and Australia experiencing extreme drought.

Groundwater levels continued to recover from their lowest levels in 2016, but regions of dry soils increased since 2017.

Permafrost temperatures continue to rise, contributing to the 30-year pattern of significant glacier melting. A total of 24 m of ice thickness have melted off glaciers since 1980.

Atmospheric concentrations of many long-lived greenhouse gases (such as CO2) continued to increase at rates at or above the average of the previous decade.

Despite its dire warnings of the state of the global climate, this chapter offers small glimmers of hope: although emissions of CFC-11 (which depletes the Earth's protective ozone layer) declined more slowly than expected, possibly delaying the recovery of the ozone layer, clear signs of ozone recovery were shown in the significant increase in upper stratospheric ozone in the Pacific Region.

Anthropogenic (manmade) aerosol emissions continued to fall over Europe, China and the eastern United States, but continued to increase over the Indian subcontinent.

Nadine was also author of the subchapter on Terrestrial Surfaces with the technical support of JRC scientist Monica Robustelli and, with JRC scientist Bernard Pinty, co-authored the subchapter on Land Surface Albedo Dynamics.

The annual State of the Climate reports

The annual State of the Climate report is an international, peer-reviewed and authoritative summary of the global climate that has been published every summer as a supplement to the Bulletin of the American Meteorological Society since 1996.

Its main function is to document the status and trajectory of many components of the climate system.

Compiled by NOAA’s Center for Weather and Climate at the National Centers for Environmental Information, the report is based on contributions from scientists from around the world. It provides a detailed update on global climate indicators, notable weather events, and other data collected by environmental monitoring stations and instruments located on land, water, ice, and in space.

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