THE LAST DECADE has been the hottest on Earth since records began in the mid-1800s.

2019 alone was one of the three warmest years on record above the Earth’s surface, according to the 2019 State of the Climate report released yesterday by the American Meteorological Society.

In Ireland, the 2018/19 winter season was the warmest on record since 1900, with an increase of 1.8 degrees Celsius.

Over half of Ireland’s weather stations set new records on monthly maximum temperatures on 25 and 26 February in 2019.

Summer 2019 was warmer than normal for most of Europe, with an increase in 2 degrees Celsius or 4 degrees Celsius in some areas, and drier – with the exception of Ireland, along with the UK, southern parts of Norway, and the eastern Mediterranean.

Temperatures in Ireland overall were above normal levels, but saw less of an increase than other countries in Western Europe, such as the Netherlands, Belgium, Luxembourg and France.

Since 2013, each year has been warmer than all other years on record.

The years between 2010 and 2019 were 0.2 degrees Celsius warmer than between 2000 and 2009, with each decade since 1980 growing warmer than the one before it.

In 2019, the increasing concentration of greenhouse gases in the atmosphere meant that middle and upper stratospheric temperatures -  that is, temperatures in the middle layer of Earth’s atmosphere – were the lowest recorded since 1979.

Carbon dioxide, nitrous oxide, and methane, which are considered greenhouse gases, all increased their presence at Earth’s surface. Particularly, the increase of methane followed a trend of a rapid rise in its concentration that began in 2007.

“For the last few State of the Climate reports, an update on the number of warmer-than-average years has held no surprises, and this year is again no different,” the report said.

“The year 2019 was among the three warmest years since records began in the mid-to-late 1800s. Only 2016, and for some datasets 2015, were warmer than 2019; all years after 2013 have been warmer than all others back to the mid-1800s.”

“Each decade since 1980 has been successively warmer than the preceding decade, with the most recent (2010–19) being around 0.2°C warmer than the previous (2000–09).”

The wildfires which ravaged Australia at the end of the year, alongside volcanic eruptions in Russia and Papua New Guinea, increased aerosol in the stratosphere to a level which had not been seen since volcanic activity at Mount Pinatubo in the Philippines in the early 1990s.

The report said that changes in the Indian Ocean may “turn the globe upside-down for our North American readership”.

“The body of water, cleaved into distinct halves marked by the strongest Indian Ocean Dipole in more than two decades, behaved as something of a center of gravity in this report, as many of the extremes and related phenomena seemed to emanate from it,” the report said.

“The strength of its signal was seen throughout the system and throughout this report: in nuisance flooding and unusual chlorophyll concentrations in and around the basin; in unprecedented tropical cyclone activity in the Arabian Sea; as historic fire and drought in Australia; and in back-to-back devastating tropical cyclones in southeast Africa.”

In 2019, glaciers continued to become thinner for the 32nd year in a row.

Most glaciers lost mass, and many also became shorter.

Storm Lorenzo, which battered Ireland in October, was one of five Category 5 storms in the western North Pacific and North Atlantic.

Lorenzo was the second deadliest storm in the North Atlantic in 2019, and produced tropical storm force winds across parts of Ireland.

Ireland saw precipitation levels of 100%-125% of normal records, while the UK and areas of France had below-normal levels.

However, low pressure during the summer months led to particularly wet season for Ireland and the UK, with the UK recording its 10th wettest summer since records began.