<img class="styles__noscript__2rw2y" src="https://s.w-x.co/util/image/w/global-temp-trends-WMO-3.20.jpg?v=at&w=485&h=273" srcset="https://s.w-x.co/util/image/w/global-temp-trends-WMO-3.20.jpg?v=at&w=485&h=273 400w, https://s.w-x.co/util/image/w/global-temp-trends-WMO-3.20.jpg?v=ap&w=980&h=551 800w" > Global temperatures in 2019 were the second-warmest on record, as analyzed by several research organizations around the world. (WMO)

At a Glance A new report catalogues the landmark weather and climate events of 2019.

Global air temperatures were the second-warmest in records going back to 1850.

Three key human-produced greenhouse gases hit record concentrations.

Drought and fire hammered Australia, while major flooding hit East Africa. The warmest oceans on record, and the second-hottest atmosphere on record, are just two markers of global climate change documented by the World Meteorological Organization (WMO) in its Statement on the State of Global Climate in 2019 , released on Tuesday.

The annual report summarizes atmospheric and oceanic change and its impacts on phenomena from marine life to human health and food security.

Last year came in just behind 2016 for global atmospheric heat in records dating back to 1850, the WMO reported. The last five years (2015-19) and the last 10 years (2010-19) were both the warmest on record.

Each decade since the 1980s has been warmer than the prior decade.

The global temperature in 2019 was about 1.9 degrees Fahrenheit above the estimated levels that prevailed in the mid-1800s, before widespread use of fossil fuels began to boost the amount of heat-trapping greenhouse gas in the atmosphere.

Earth's oceans are an even starker index of steady climate change because oceans retain more than 90% of the extra heat being trapped by human-produced greenhouse gases. 2019 temperatures in the uppermost 6,500 feet of the ocean were the highest on record, said the WMO. The previous record was set just the year before, in 2018.

"Given that greenhouse gas levels continue to increase, the warming will continue," said UN Secretary-General and WMO Secretary-General Petteri Taalas in a news release on Tuesday. The WMO report was released in a press conference at the UN’s New York office.

Taalas cited the latest decadal forecast from the UK Met Office, which predicts that a new annual global air temperature record is likely in the next five years.

"It is a matter of time," said Taalas.

<img class="styles__noscript__2rw2y" src="https://s.w-x.co/util/image/w/CO2-methane-N2O.png?v=at&w=485&h=273" srcset="https://s.w-x.co/util/image/w/CO2-methane-N2O.png?v=at&w=485&h=273 400w, https://s.w-x.co/util/image/w/CO2-methane-N2O.png?v=ap&w=980&h=551 800w" > Globally averaged mole fraction (measure of concentration), from 1984 to 2018, of carbon dioxide in parts per million (left), methane in parts per billion (centre) and nitrous oxide in parts per billion (right). The red line is the monthly mean mole fraction with the seasonal variations removed; the blue dots and line show the monthly averages. (WMO Global Atmosphere Watch)

Greenhouse Gases Hit New Records

All three of the most prevalent human-produced greenhouse gases hit record annual-average concentrations in the atmosphere as of 2018, the most recent year for complete global data:

– Carbon dioxide: 408 parts per million

– Methane: 1,869 parts per billion

– Nitrous oxide: 331 parts per billion

Carbon dioxide (CO2) concentrations have risen in every year since regular measurements began in 1958 at Mauna Loa in Hawaii. That year, the average CO2 level was around 315 parts per million.

Emissions of carbon dioxide from fossil fuel use held roughly steady from 2014 to 2019, and preliminary estimates show that they increased by 0.6% in 2019. The slower growth of emissions in recent years has been attributed to increases in energy efficiency and alternative energy and a decline in the use of coal for electric power.

However, the CO2 concentration in the atmosphere has continued to climb each year, in much the same way as overspending by a reduced amount still adds to one’s debt.

Carbon dioxide emissions could drop slightly in 2020, depending on the economic impact of the novel coronavirus.

Sea level also hit a new record high in 2019. Average global sea level has risen about 3.4 inches since 1993, when high-resolution altimetry measurement began. The rise has accelerated in recent years, the report notes.

"A greater loss of ice mass from the ice sheets is the main cause of the accelerated rise in the global mean sea level, on top of steady increases from the expansion of ocean waters driven by warming," said the report.

Ocean warming has led to severe episodes of coral bleaching over the past decade, especially across Australia’s Great Barrier Reef. By 2019, coral cover in the northern parts of the reef had recovered only modestly from two major bleaching events in the last five years.

Very warm waters in early 2020 have led to another widespread bleaching event at the reef.

<img class="styles__noscript__2rw2y" src="https://s.w-x.co/util/image/w/GettyImages-1191119050-nowra.jpg?v=at&w=485&h=273" srcset="https://s.w-x.co/util/image/w/GettyImages-1191119050-nowra.jpg?v=at&w=485&h=273 400w, https://s.w-x.co/util/image/w/GettyImages-1191119050-nowra.jpg?v=ap&w=980&h=551 800w" > Firefighters struggle against the strong wind on Dec. 31, 2019, in an effort to secure nearby houses from bushfires near the town of Nowra in the Australian state of New South Wales. (Saeed KhanAFP via Getty Images)

Heat, Floods and Drought

The year’s most significant heat waves struck Europe with ferocity in late June and late July, bringing unprecedented readings to several countries and dozens of cities. Initial estimates suggest this heat led to more than 5,000 "excess deaths" (deaths that would not have otherwise occurred) in France, the Netherlands and the United Kingdom, according to the WMO report.

A stark contrast developed in 2019 between hot, parched conditions in Indonesia and Australia and unusually wet conditions in eastern Africa. This was partially the result of an amplified Indian Ocean Dipole that shifted rising air toward the west.

Australia experienced one of its hottest, driest years on record, fueling intense fires that raged from late 2019 into early 2020.

<img class="styles__noscript__2rw2y" src="https://s.w-x.co/util/image/w/GettyImages-1180769321-south-sudan-flood.jpg?v=at&w=485&h=273" srcset="https://s.w-x.co/util/image/w/GettyImages-1180769321-south-sudan-flood.jpg?v=at&w=485&h=273 400w, https://s.w-x.co/util/image/w/GettyImages-1180769321-south-sudan-flood.jpg?v=ap&w=980&h=551 800w" > An aerial picture shows a flooded area that has been isolated for about a month and half due to the heavy rain in Pibor Town, Boma state, eastern South Sudan, on Nov. 6, 2019. (Peter Louis/AFP via Getty Images)

Several tropical cyclones moved into the Horn of Africa, contributing to the heaviest October-to-December rainfall in decades in the region. The rains followed an exceptionally dry period in March and April, a climatic whiplash that has left the region vulnerable to high food insecurity.

Some 8.1 million people across the region have been displaced due to weather and climate stress as well as political conflicts.

A locust outbreak—Kenya’s most severe in 70 years—is underway and expected to expand into spring. "Large swarms such as the ones that appeared over Kenya can eat the same amount of food as 80 million people in a single day, and affected areas can experience the total loss of crops and fodder," said the WMO report.

Extreme rainfall also doused much of the U.S. Midwest, contributing to major flooding in spring 2019. The contiguous U.S. saw its wettest 12-month period on record from July 2018 to June 2019.

The Weather Company’s primary journalistic mission is to report on breaking weather news, the environment and the importance of science to our lives. This story does not necessarily represent the position of our parent company, IBM.