2015 was the hottest year in history, that is, since records began in 1880. We are close to a full degree of increase in average global temperature, already more than halfway to the 1.5 degrees Celsius threshold so frequently cited during the Paris climate conference (Cop 21). The increase beyond which many island states and coastal countries could end up underwater and millions of people could be forced to migrate. The news was announced by Nasa, the American space agency, by Noaa, the American agency for oceans and the atmosphere, and by the Met office, its British counterpart.

The temperature recorded last year was 0.9 degrees higher than the reference global average of 13.9 degrees. An increase that takes into account both land and ocean temperatures. A figure that has literally shattered the previous record, which dates back just twelve months earlier, to 2014, when the year-on-year increase had been 0.74 degrees (+0.16 degrees in a single year).

Ranking (1 = the hottest year from 1880 to 2015)	Year	Anomaly in °C
1	2015	0.90
2	2014	0.74
3	2010	0.70
4	2013	0.66
5	2005	0.65
6	1998	0.63
6	2009	0.63
8	2012	0.62
9	2003	0.61
9	2006	0.61
9	2007	0.61
12	2002	0.60
13	2004	0.57
13	2011	0.57
15	2001	0.54
15	2008	0.54

With 2015, the negative and rising temperature trend is confirmed (see table). It is worth noting that the top four positions in the ranking of the hottest years on record are occupied by the last three years.

"2015 was an anomalous year even when considered against the long-term global warming trend," said Gavin Schmidt, director of Nasa's Goddard institute for space studies. The jump of 0.16 degrees from 2014 to 2015 is, indeed, truly remarkable.

The message is clear: the Paris agreement needs to be implemented as soon as possible, because the climate is anything but on our side. The window seems to be narrowing year by year, and if action is not taken immediately, halting global warming below a manageable threshold risks becoming an impossible task.

The Potsdam institute for climate impact research (Pik), a German organisation that has long been a key player in providing data and guidelines on how to address climate change, is in no doubt: "The news about the 2015 global average temperature record shows that climate change is a reality," declared Professor Wolfgang Lucht of the Pik, who is equally clear on what the definitive solution must be: "We must put an end to the era of fossil fuels."