The world is "way off track" for meeting targets to curb rising temperatures and time is running out to combat the climate crisis, United Nations experts have warned.
Scientists also said the threat was greater than the coronavirus, and world leaders must not be diverted away from climate action.
A report compiled by the UN’s World Meteorological Organisation (WMO) highlights 2019’s increasing heat, accelerating sea level rises, and extreme weather – and the impact they have on people and wildlife.
Last year was the second hottest year on record for the world, with a global average temperature of 1.1C above pre-industrial levels, the WMO’s statement on the state of the global climate in 2019 confirms.
The five years from 2015-2019 were the five warmest years on record and 2010-2019 was the hottest decade since records began in the 19th century.
Each decade since the 1980s has been hotter than any preceding decade stretching back to 1850, according to the report, which has input from national meteorological services, international experts, scientific institutions and UN agencies.
Five warmest years on record since records began, according to UN report.
The trends continue in 2020, with the report published in the wake of the hottest January on record globally and some parts of the northern hemisphere, including Europe, experiencing an unusually warm winter.
Antarctica has reported new temperature highs, accompanied by large-scale ice melt and a fracturing glacier which will have "repercussions for sea level rise", WMO secretary-general Petteri Taalas said.
This year countries are expected, under the international Paris Agreement on climate change, to increase their action to tackle greenhouse gas emissions to prevent the worst impacts of global warming.
In a foreword to the report, UN secretary-general Antonio Guterres said: "We are currently way off track to meeting either the 1.5C or 2C targets that the Paris Agreement calls for.
Hottest decade on record since records began in 19th Century, according to UN report.
He added: "This report outlines the latest science and illustrates the urgency for far-reaching climate action."
Prof Taalas said: "Given that greenhouse gas levels continue to increase, the warming will continue."
He added it was a matter of time before the world had a new record hot year - with predictions it will come within five years.
Alongside temperature increases, rainfall changes had a major impact on several countries and sea levels were rising at an increasing pace, exposing coastal areas and islands to a greater risk of flooding and submersion, he said.
The report found record high temperatures from Australia to India, Japan, and Europe hit people’s health and wellbeing.
New national record temperature set in the UK in 2019.
There were two major heatwaves in Europe, in June and July, with new national temperature records set in the UK, where the thermometer hit 38.7C, as well as in Germany, the Netherlands, Belgium, Luxembourg and France.
Climatic changes mean dengue is spreading, with around half the world population now at risk of infection and a large increase in cases in 2019.
World hunger is on the rise again, and an estimated 22 million people worldwide were forced to leave their homes by events such as floods and storms.
The contiguous US, excluding Alaska, Hawaii and other islands, experienced the highest 12-month rainfall on record from July 2018 to June 2019, and the country lost an estimated 20 billion US dollars (£15 billion) from flooding last year.
Some parts of the Arctic also burned - an extremely rare occurrence - and sea ice in the region continued to decline.
The Greenland ice sheet saw 329 billion tonnes of ice loss in 2019, well above the average for recent years, and glaciers continue to melt.
Sea levels were at record highs in 2019, and at least 84% of the oceans experienced at least one marine heatwave.
Warming ocean temperatures, along with more acidic water and lower oxygen levels, are having an impact on marine wildlife and habitats such as coral, the report said.