World Meteorological Organization (WMO)
The year 2015 made history, with shattered temperature records, intense heatwaves, exceptional rainfall, devastating drought and unusual tropical cyclone activity, according to the World Meteorological Organization. That record-breaking trend has continued in 2016.
The WMO Statement on the Status of the Climate in 2015 gave details of the record land and sea surface temperatures, unabated ocean warming and sea level rise, shrinking sea ice extent, and extreme weather events around the world.
It was released to coincide with World Meteorological Day on 23 March, which has the theme “Hotter, drier, wetter. Face the Future.”
“The future is happening now,” said WMO Secretary-General Petteri Taalas.
“The alarming rate of change we are now witnessing in our climate as a result of greenhouse gas emissions is unprecedented in modern records,” said Mr Taalas.
The global average surface temperature in 2015 broke all previous records by a wide marging, at about 0.76° Celsius above the 1961-1990 average because of a powerful El Niño and human-caused global warming. With 93% of excess heat stored in the oceans, ocean heat content down to 2 000 meters also hit a new record.
January and February 2016 set yet more new monthly temperature records, with the heat especially pronounced in the high northern latitudes. Arctic sea ice extent was at a satellite-record low for both months, according to NASA and the U.S. National Oceanic and Atmospheric Administration. Greenhouse gas concentrations crossed the symbolic and significant 400 parts per million threshold.
“The startlingly high temperatures so far in 2016 have sent shockwaves around the climate science community,” said David Carlson, Director of the World Climate Research Programme, which is co-sponsored by WMO.
“Our planet is sending a powerful message to world leaders to sign and implement the Paris Agreement on climate change and cut greenhouse gases now before we pass the point of no return,” said Mr Taalas.
“Today the Earth is already 1°C hotter than at the start of the twentieth century. We are halfway to the critical 2°C threshold. National climate change plans adopted so far may not be enough to avoid a temperature rise of 3°C, but we can avert the worst-case scenarios with urgent and far-reaching measures to cut carbon dioxide emissions,” said Mr Taalas.
In addition to mitigation, it is essential to strengthen climate change adaptation by investing in disaster early warning systems, as well as climate services like drought, flood and heat-health management tools, stressed Mr Taalas.
Key Findings of Statement on Status of Climate in 2015
Sea surface temperatures and ocean heat
Large areas of the oceans saw significant warmth. In particular, the tropical central and eastern Pacific was much warmer than average because of El Niño. Global ocean heat content was record high through both the upper 700 m and 2 000 m levels. Increased ocean heat content accounts for about 40% of the observed global seal level increase over the past 60 years and is expected to make a similar contribution to future sea-level rise. Sea level, as measured by satelllites and traditional tide gauges was the highest ever recorded.
Arctic Sea Ice
The daily maximum extent of Arctic sea ice on 25 February 2015 was the lowest on record (this record was beaten in 2016), and the minimum Arctic sea-ice extent on 11 September was the fourth lowest.
Many countries saw intense heatwaves. The most devastating ones in terms of human impact were in India and Pakistan. Asia, as a continent, had its hottest year on record, as did South America.
Western and Central Europe recorded an exceptionally long heatwave, with temperature crossing or approaching 40°C in several places. Several new temperature records were broken (Germany 40.3°C, Spain 42.6°C, UK 36.7°C).
North West USA and Western Canada suffered from a record wildfire season, with more than 2 million hectares were burned during summer in Alaska alone.
Global precipitation in 2015 was close to the long-term average. But within this overall figure, there were many cases of extreme rainfall, with 24-hour totals exceeding the normal monthly mean.
For instance, in Africa, Malawi suffered its worst flooding in memory in January. An active West African monsoon saw exceptional seasonal rainfall totals. The West coast of Libya received more than 90mm of rain in 24 hours in September, compared to the monthly average of 8mm. The Moroccan city of Marrakech received 35,9 mm of rain in one hour in August, more than 13 times the monthly normal.
The powerful El Niño meant that 2015 was wet in many subtropical parts of South America (including Peru, northern Chile, Bolivia, Paraguay, southern Brazil and northern Argentina), and in parts of the southern United States and northern Mexico.
Severe drought affected southern Africa, with 2014/2015 as the driest season since 1932/1933, with major repercussions for agricultural production and food security. El Niño induced drought exacerbated forest fires in Indonesia, impacting air quality both in Indonesia neighbouring countries.
The northern part of South America suffered a severe drought including North East Brazil, Columbia and Venezuela, hitting the agriculture, water and energy sectors. Parts of the Caribbean and Central America were also severely affected.
Globally the number of tropical storms, cyclones and typhoons was not far from the average, but some unusual events were recorded. Tropical cyclone Pam made landfall over Vanuatu as a category 5 cyclone on 13 March 2015, causing widespread devastation. Patricia hit Mexico on 20 October as the strongest hurricane on record in either the Atlantic or eastern North Pacific basins, with maximum sustained wind speeds of 346 km/h. An extremely rare tropical cyclone, Chapala, made landfall in Yemen at the start of November, leading to substantial flooding. This was immediately followed by Cyclone Megh, which hit the same area.
World Meteorological Day
World Meteorological Day commemorates the coming into force on 23 March 1950 of the Convention establishing the World Meteorological Organization. It showcases the essential contribution of National Meteorological and Hydrological Services to the safety and wellbeing of society.
The theme Hotter, Drier, Wetter. Face the Future highlights the challenges of climate change and the path towards climate-resilient societies.
The increase in hot days, warm nights and heatwaves will affect public health. These risks can be reduced by heat-health early warning systems that provide timely alerts to decision-makers, health services and the general public.
Droughts must be addressed more proactively through integrated drought management, which embraces guidance on effective policies and land management strategies and shares best practices for coping with drought.
In the event of heavy precipitation and floods, impact-based forecasts enable emergency managers to be prepared in advance. Integrated flood management is a long-term holistic approach to minimizing the risks of flooding.
Building climate and weather resilient communities is a vital part of the global strategy for achieving sustainable development. The WMO community will continue to support countries in pursuing sustainable development and tackling climate change through the provision of the best possible science and of operational services for weather, climate, hydrology, oceans and the environment.