Alarming news for the climate. In 2017, the concentration of greenhouse gases in the atmosphere hit levels never seen before. And it was the third hottest year on record.
Bad news for those who care about the health of our planet. The latest edition of the annual State of the climate report, produced by the National Oceanic and Atmospheric Administration (Noaa) and published in the Bulletin of the American Meteorological Society, lays out a series of alarming data that unequivocally demonstrate how climate change is a tangible reality. The publication is the result of work by more than five hundred scientists from 65 different countries.
Global temperatures have hit unprecedented peaks over the past three years: in first place among the hottest years on record is 2016, in second place 2015, and in third place 2017. If only the years in which the atmospheric phenomenon known as El Niño did not occur are taken into account, then the year just passed becomes the hottest of all.
2017 was also the year in which the concentration of the main greenhouse gases in the atmosphere (CO2, methane and N2O) reached levels never recorded before. Their average global concentration stood at 405 parts per million. Such a figure had never been recorded using modern methods, which have been in use for 38 years, nor even when making estimates for earlier periods.
Sea levels are rising at an average of 3.1 centimetres per decade. As a result, they now exceed the 1993 average by 7.7 centimetres. The surface temperature of the water remains slightly lower than that recorded in 2016, but the long-term upward trend is confirmed.
The maximum annual extent of Arctic sea ice is the lowest in the past 38 years — that is, over the entire period during which these measurements have been taken. The minimum extent is also 25 per cent below the average, making it the eighth smallest on record.
The extent of Antarctic sea ice is also well below the average for the three decades between 1981 and 2010. On 1 March 2017 it fell to 2.1 million square kilometres: since satellite measurements began in 1978, such a low daily value had never been observed.
