As the year ends, a report from the World Meteorological Organization (WMO) says that 2017 was among the top 3 hottest years. This would mean three record-breaking hot years consecutively: 2015, 2016 and now 2017.
The report also highlighted the devastating floods, hurricanes, droughts, and heatwaves in 2017 and their long-term impact on key indicators of climate change like rising sea level, increasing concentration of CO2, and acidification of oceans.
The average global temperature from January to September 2017 was around 1.1°C above the pre-industrial era. Due to the effect of a powerful El Niño, 2016 is set to still remain the warmest year on record, with 2017 and 2015 being at the second or third place.
Petteri Taalas, the secretary general of the WMO, says: “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. We have witnessed extraordinary weather, including temperatures topping 50C 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.”
The hat-trick of record-breaking hot years
This recent increase in average global temperatures establishes a renewed warming trend, which had slowed its pace slightly in the last decade, which lead to the short-lived anticipation that the pace of global warming is slowing. The latest research has also found that the levels of carbon dioxide in the atmosphere are now higher than it has ever been in 800,000 years.
As per the World Health Organization (WHO), the detrimental impact of heatwaves is not only on the warming trend but also on people’s livelihood.
Studies claim that the overall risk of heat-related illness or death has constantly steadily since 1980, with around 30% of the world’s population dwelling in climatic conditions that deliver prolonged extreme heatwaves. Between 2000 and 2016, the number of vulnerable people exposed to heatwave events has increased by approximately 125 million.
In 2016, nearly 24 million people were displaced from their habitats during weather-related disasters. Majority of these internal displacements were as a result of floods or storms and occurred in the Asia-Pacific region.
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The latest International Monetary Fund (IMF) World Economic Outlook indicates that adverse consequences are concentrated in countries with relatively hot climates and which are home to close to 60% of the current global population.
The WMO report is based on five independently maintained global temperature datasets. Temperatures in 2016 were hiked by an overpoweringly strong El Niño. 2017, so far, has been the hottest year on record without an El Niño influence. The five-year average 2013-2017 is 0.40°C warmer than the 1981-2010 average and 1.03°C above the pre-industrial period and is likely to be the hottest on record.
Impact on the ice caps
Arctic sea-ice level was 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.
The Arctic sea level was minimum in mid-September, 25- 31% below the 1981-2010 average, and among the eight smallest minimum extents on record. The ten smallest minimum extents have all occurred since 2007.
Antarctic sea ice extent was also well below average. The annual minimum extent in early March was record low, and the annual maximum extent in mid-October was at or near record low levels. Sea ice conditions in the Antarctic have been highly variable over the past several years with the record large sea ice extents occurring as recently as 2015.
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Northern Hemisphere snow cover extent was 10.54 million square km, near the median value in the 1967-2017 satellite record.
The Greenland ice sheet saw an increase of more than 40 billion tons of ice due to above-average snowfall and a short melt season. Despite the gain in overall ice mass this year, it is only a small departure from the declining trend, with the Greenland ice sheet having lost approximately 3,600 billion tons of ice mass since 2002.
Increase in oceanic acidification
Global oceanic heat in 2017 has also been record high. According to the Intergovernmental Oceanographic Commission of UNESCO, the ocean absorbs up to 30% of the annual emissions of anthropogenic CO2 in the atmosphere, which considerably helps in mitigating the impacts of climate change.
But the damage is that 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 steadily declined, from values above 8.10 in the early 1980s to between 8.04 and 8.09 in the last five years.
Ocean acidification is having a severely adverse effect on the health of coral reefs and the existence of many marine organisms.
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