On this first day of COP23, the WMO (World Meteorological Organization) released its report on the State of the Climate 2017, condensing in a single volume everything that happened in this year.
WMO report highlights impacts on human safety, well-being and environment
6 November 2017 (WMO) -It is very likely that 2017 will be one of the three hottest years on record, with many high-impact events including catastrophic hurricanes and floods, debilitating heatwaves and drought. Long-term indicators of climate change such as increasing carbon dioxide concentrations, sea level rise and ocean acidification continue unabated. Arctic sea ice coverage remains below average and previously stable Antarctic sea ice extent was at or near a record low.
The World Meteorological Organization’s provisional Statement on the State of the Climate says the average global temperature from January to September 2017 was approximately 1.1°C above the pre-industrial era. As a result of a powerful El Niño, 2016 is likely to remain the warmest year on record, with 2017 and 2015 being second and/or third. 2013-2017 is set to be the warmest five-year period on record
The past three years have all been in the top three years in terms of temperature records. This is part of a long term warming trend,” said WMO Secretary-General Petteri Taalas. “We have witnessed extraordinary weather, including temperatures topping 50 degrees Celsius in Asia, record-breaking hurricanes in rapid succession in the Caribbean and Atlantic reaching as far as Ireland, devastating monsoon flooding affecting many millions of people and a relentless drought in East Africa.
Global temperatures in 2017
Global mean temperature for the period January to September 2017 was 0.47°±0.08°C warmer than the 1981-2010 average (estimated at 14.31°C). This represents an approximately 1.1°C increase in temperature since the pre-industrial period. Parts of southern Europe, including Italy, North Africa, parts of east and southern Africa and the Asian part of the Russian Federation were record warm and China was the equal warmest. The northwestern USA and western Canada were cooler than the 1981-2010 average. Temperatures in 2016 and, to an extent, 2015, were boosted by an exceptionally strong El Niño. 2017 is set to be the warmest year on record without an El Niño influence. The five-year average 2013-2017 is provisionally 0.40°C warmer than the 1981-2010 average and approximately 1.03°C above the pre-industrial period and is likely to be the hottest on record.
Southern South America (particularly in Argentina), western China, and parts of southeast Asia were wetter than average. January to September was the wettest on record for the contiguous United States. Rainfall was generally close to average in Brazil, and near to above average in northwest South America and Central America, easing droughts associated with the 2015-16 El Niño. The 2017 rainy season saw above-average rainfall over many parts of the Sahel, with flooding in some regions (especially in Niger).
Ice and snow:
Arctic sea-ice extent was well below average throughout 2017 and was at record-low levels for the first four months of the year, according to the National Snow and Ice Data Center and the Copernicus Climate Change Service. The Arctic annual maximum extent in early March was among the five lowest in the 1979-2017 satellite record, and according to the NSIDC’s data was record low. The five lowest maximum extents have occurred since 2006.
Global sea surface temperatures are on track to be among the three highest on record. Global ocean heat content in 2017 to date has been at or near record high levels. Elevated tropical sea surface temperatures which contribute to coral bleaching were not as widespread as during the 2015-16 El Niño. But some significant coral bleaching did still occur, including the Australia’s Great Barrier Reef. UNESCO reported in June that all but three of the 29 coral reefs with World Heritage listing had experienced temperatures consistent with bleaching at some point in the 2014-2017 period.
According to the Intergovernmental Oceanographic Commission of UNESCO the ocean absorbs up to 30% of the annual emissions of anthropogenic CO2 in the atmosphere, helping to alleviate the impacts of climate change on the planet. However, this comes at a steep ecological cost, as the absorbed CO2 changes acidity levels in the ocean. Since records at Aloha station (north of Hawaii) began in the late 1980s, seawater pH has progressively fallen, from values above 8.10 in the early 1980s to between 8.04 and 8.09 in the last five years.
The rate of increase in CO2 from 2015 to 2016 was the highest on record, 3.3 parts per million/year, reaching 403.3 parts per million. Global average figures for 2017 will not be available until late 2018. Real-time data from a number of specific locations indicate that levels of CO2, methane and nitrous oxide continued to increase in 2017.
Extreme Events and Impacts
The North Atlantic had a very active season. The Accumulated Cyclone Energy (ACE) index, a measure of the aggregate intensity and duration of cyclones, had its highest monthly value on record in September. Three major and high-impact hurricanes occurred in the North Atlantic in rapid succession, with Harvey in August followed by Irma and Maria in September. Harvey made landfall in Texas as a category 4 system and remained near the coast for several days, producing extreme rainfall and flooding. Provisional seven-day rainfall totals reached as high as 1539 mm at a gauge near Nederland, Texas, the largest ever recorded for a single event in the mainland United States.
The WMO Expert Team on Climate Impacts on Tropical Cyclones found that, whilst there is no clear evidence that climate change is making the occurrence of slow-moving, land-falling hurricanes such as Harvey more or less frequent, it is likely that human-induced climate change makes rainfall rates more intense, and that ongoing sea-level rise exacerbates storm surge impacts.
Exceptionally heavy rain triggered a landslide in Freetown, Sierra Leone in August, killing more than 500 people. Freetown received 1459.2 mm of rain in two weeks, about four times higher than average. Heavy rainfall contributed to a landslide in Mocoa, southern Colombia, in April, with at least 273 deaths reported.
Flooding affected many parts of Peru in March, killing 75 people and making 70,000 homeless. The Food and Agriculture Organization reported that there were significant crop production losses, particularly maize. Flooding of this type typically affects Peru during the late phase of El Niño events. Whilst there was no Pacific-wide El Niño during 2017, sea surface temperatures near the Peruvian coast in March were 2°C or more above average and similar to El Niño values.
Parts of east Africa continued to be seriously affected by drought. Following well-below-average rainfall in 2016, the 2017 “long rains” season (March to May) was also dry in many parts of Somalia, the northern half of Kenya, and southeastern Ethiopia.
FAO reported that in Somalia, as of June 2017, more than half of the cropland was affected by drought, with herds reduced by 40-60% since December 2016. WFP estimates that the number of people on the brink of famine in Somalia has doubled to 800 000 since February 2017, with half the country needing assistance. WFP has confirmed that more than 11 million people are experiencing severe food insecurity in Somalia, Ethiopia and Kenya. From November 2016 to mid-June 2017, more than 760 000 drought-related internal displacements in Somalia were recorded by the Protection and Return Monitoring Network (PRMN), a United Nations High Commissioner for Refugees (UNHCR) led project.
Many parts of the Mediterranean experienced dry conditions. The most severe drought was in Italy, hitting agricultural production and causing a 62% drop in olive oil production compared to 2016. Rainfall averaged over Italy for January-August 2017 was 36% below average. It was also Italy’s hottest January-August on record, with temperatures 1.31°C above the 1981-2010 average. Other dry areas included many parts of Spain and Portugal.
An extreme heatwave affected parts of South America in January. In Chile, numerous locations had their highest temperature on record, including Santiago (37.4°C). In Argentina, the temperature reached 43.5°C on 27 January at Puerto Madryn, the highest ever recorded so far south (43°S) anywhere in the world.
Exceptional heat affected parts of southwest Asia in late May. On 28 May, temperatures reached 54.0°C in Turbat, in the far west of Pakistan near the Iranian border, and also exceeded 50°C in Iran and Oman. A temperature of 53.7°C was recorded at Ahwaz, Iran on 29 June, and Bahrain experienced its hottest August on record.
The Chinese city of Shanghai and the Hong Kong Observatory reported new records of 40.9°C and 36.6 °C during summer.
Extreme heat and drought contributed to many destructive wildfires.
Chile had the most significant forest fires in its history during the 2016-2017 summer, after exceptionally dry conditions during 2016 followed by extreme heat in December and January. 11 deaths were reported, and a total of 614 000 hectares of forest were burnt, easily the highest seasonal total on record and eight times the long-term average. There were also significant fires during the 2016-2017 Southern Hemisphere summer in various parts of eastern Australia and in the Christchurch region of New Zealand, whilst the southern South African town of Knysna was badly affected by fire in June.
It was a very active fire season in the Mediterranean. The worst single incident occurred in central Portugal in June, with 64 deaths. There were further major fire outbreaks in Portugal and northwestern Spain in mid-October, exacerbated by strong winds associated with Hurricane Ophelia.. Other significant fires affected countries including Croatia, Italy and France.
Other noteworthy events
Severe cold and snow affected parts of Argentina in July. After heavy snow had fallen the previous day, the temperature reached −25.4°C in Bariloche on 16 July, 4.3°C below the previous lowest temperature on record there. Other regions where record low temperatures occurred in 2017 included some locations in inland southeastern Australia in early July, where Canberra had its lowest temperature (−8.7°C) since 1971, and the Gulf region in the Middle East in early February.
The United States had its most active tornado season since 2011, with a preliminary total of 1 321 tornadoes in the January to August period, including the second-most active January on record.
The World Meteorological Organization is the United Nations System’s authoritative voice on Weather, Climate and Water
- Whole article: https://public.wmo.int/en/media/press-release/2017-set-be-top-three-hottest-years-record-breaking-extreme-weather
- Report: https://public.wmo.int/en/media/press-release/2017-set-be-top-three-hottest-years-record-breaking-extreme-weatherhttp://ane4bf-datap1.s3-eu-west-1.amazonaws.com/wmocms/s3fs-public/ckeditor/files/2017_provisional_statement_text_-_updated_04Nov2017_1.pdf