|Photo: Clive Simpson|
Issuing its annual statement on the State of the Global Climate ahead of World Meteorological Day today (21 March), the World Meteorological Organization (WMO) said extreme weather and climate conditions have continued into 2017.
Its report, based on multiple international datasets maintained independently by global climate analysis centres and information submitted by dozens of WMO and research institutes, is regarded as an authoritative source of reference.
Because the social and economic impacts of climate change have become so important, WMO partnered with other United Nations organisations for the first time to include information on these impacts.
“This report confirms that the year 2016 was the warmest on record – a remarkable 1.1C above the pre-industrial period and 0.06C above the previous record set in 2015. This increase in global temperature is consistent with other changes occurring in the climate system,” said WMO secretary-general Petteri Taalas.
“Globally averaged sea surface temperatures were also the warmest on record, global sea levels continued to rise and Arctic sea-ice extent was well below average for most of the year,” he added..
“With levels of carbon dioxide in the atmosphere consistently breaking new records, the influence of human activities on the climate system has become more and more evident,” said Mr Taalas.
The increased power of computing tools and the availability of long term climate data have made it possible today, through attribution studies, to demonstrate clearly the existence of links between man-made climate change and many cases of high impact extreme events in particular heatwaves.
Each of the 16 years since 2001 has been at least 0.4C above the long-term average for the 1961-1990 base period, used by WMO as a reference for climate change monitoring. Global temperatures continue to be consistent with a warming trend of 0.1 C to 0.2C per decade, according to the WMO report.
The powerful 2015/2016 El Niño event boosted warming in 2016, on top of long-term climate change caused by greenhouse gas emissions. Temperatures in strong El Niño years, such as 1973, 1983 and 1998, are typically 0.1 C to 0.2C warmer than background levels, and 2016’s temperatures are consistent with that pattern.
Global sea levels rose very strongly during the El Niño event, with the early 2016 values reaching new record highs. Global sea ice extent dropped more than 4 million square kilometres below average in November, an unprecedented anomaly for that month.
The very warm ocean temperatures contributed to significant coral bleaching and mortality was reported in many tropical waters, with important impacts on marine food chains, ecosystems and fisheries.
Carbon dioxide levels in the atmosphere reached the symbolic benchmark of 400 parts per millions in 2015 – the latest year for which WMO global figures are available – and will not fall below that level for many generations to come because of the long-lasting nature of CO2.
Among some of the most extreme events in 2016 were severe droughts that brought food insecurity to millions in southern and eastern Africa and Central America. Hurricane Matthew caused widespread suffering in Haiti as the first category four storm to make landfall since 1963, and inflicted significant economic losses in the United States of America, while heavy rains and floods affected eastern and southern Asia.
Newly released studies, which are not included in WMO’s report, indicate that ocean heat content may have increased even more than previously reported. Provisional data also indicates that there has been no easing in the rate of increase in atmospheric carbon dioxide concentrations.
“Even without a strong El Niño in 2017, we are seeing other remarkable changes across the planet that are challenging the limits of our understanding of the climate system. We are now in truly uncharted territory,” said World Climate Research Programme director David Carlson.
At least three times so far this winter, the Arctic has witnessed the Polar equivalent of a heatwave, with powerful Atlantic storms driving an influx of warm, moist air. This meant that at the height of the Arctic winter and the sea ice refreezing period, there were days which were actually close to melting point. Antarctic sea ice has also been at a record low, in contrast to the trend in recent years.
Scientific research indicates that changes in the Arctic and melting sea ice is leading to a shift in wider oceanic and atmospheric circulation patterns. This is affecting weather in other parts of the world because of waves in the jet stream – the fast moving band of air which helps regulate temperatures.
Thus, some areas, including Canada and much of the USA, were unusually balmy, whilst others, including parts of the Arabian peninsula and North Africa, were unusually cold in early 2017.
In the USA alone, 11,743 warm temperature records were broken or tied in February, according to the US National Oceanic and Atmospheric Administration. Prolonged and extreme heat in January and February affected New South Wales, southern Queensland, South Australia and northern Victoria, and saw many new temperature records.
Andrew Challinor, Professor of Climate Impacts at the University of Leeds, said: “The trend in extremes continues – as anyone shopping for salads and veg earlier this year will know. This new evidence comes just days after parliament discussed the independent report they commissioned on the implications of climate change for UK food security.
“Current government strategy emphasises the ability of markets to even out price fluctuations and ensure food supply. The independent report emphasises the need for more joined up thinking across governments and internationally.”
Prof Sir Robert Watson, Director of Strategic Development at the Tyndall Centre for Climate Change Research, University of East Anglia, said: “While the data show an ever increasing impact of human activities on the climate system, the Trump Administration and senior Republicans in Congress continue to bury their heads in the sand and state that climate change is a hoax and does not need to be addressed. We are now living in an evidence-free world, where facts are irrelevant.
“Our children and grandchildren will look back on the climate deniers and ask how they could have sacrificed the planet for the sake of cheap fossil fuel energy when the cost of inaction exceeds the cost of a transition to a low-carbon economy.
“How much more evidence does the world need to recognise the dangers confronting our society? The pledges of the Paris agreement are inadequate to limit human-induced climate change to 2C and need to be strengthened significantly – there is no time to lose.”