The planet had its hottest June on record last month, with ocean warming strengthened by climate change and the El Nino weather pattern, the European Union's climate monitor has said.
The announcement from the EU monitor Copernicus marked the latest in a series of records for a year that has already seen a drought in Spain and fierce heat waves in China and the United States.
"The month was the warmest June globally at just over 0.5 degrees Celsius above the 1991-2020 average, exceeding June 2019 - the previous record - by a substantial margin," the EU monitoring service Copernicus said in a statement.
Temperatures reached June records across northwest Europe while parts of Canada, the United States, Mexico, Asia and eastern Australia "were significantly warmer than normal", Copernicus noted.
On the other hand it was cooler than normal in western Australia, the western United States and western Russia, it said.
It was the latest in a series of heat records over recent years, reflecting the impact of global warming driven by greenhouse gases released from human activity.
Met Éireann has said Ireland can expect more frequent and extreme weather events, including higher temperatures and thunderstorms, due to climate change.
According to Met Éireann, average temperatures for June in Ireland exceeded 16 degrees Celsius for the first time, breaking the previous June record - set in 1940 - by more than half a degree.
Preliminary readings published yesterday by US meteorologists indicated Tuesday was the hottest day ever recorded, based on data from the US National Oceanic and Atmospheric Administration's National Centers for Environmental Prediction.
Copernicus noted that sea surface temperatures were higher globally than any previous June on record, with "extreme marine heatwaves" around Ireland, Britain and the Baltic.
Antarctic sea ice reached its lowest extent for June since satellite observations began, at 17% below average.
C3S scientist Julien Nicolas told AFP the June record was driven largely by "very warm ocean surface temperatures" in the Pacific and Atlantic due to El Nino, a periodic warming phenomenon.
"On top of that is this warming trend of the ocean absorbing 90% of heat released by human activity," he added.
The global temperature was 0.53 C above the 30-year average at an average of 16.51C (61.72F), he calculated.
"June 2023 is way above the others. This is the kind of anomaly we are not used to," Dr Nicolas said.
Petteri Taalas, secretary-general of the UN's World Meteorological Organization, warned on Monday that El Nino "will greatly increase the likelihood of breaking temperature records and triggering more extreme heat in many parts of the world and in the ocean."
He urged governments "to mobilise preparations to limit the impacts on our health, our ecosystems and our economies."
El Nino is a naturally occurring pattern associated with increased heat worldwide, as well as drought in some parts of the world and heavy rains elsewhere.
In addition, human activity - mainly the burning of fossil fuels - is continuing to emit roughly 40 billion tonnes of planet-warming CO2 into the atmosphere every year.
As well as withering crops, melting glaciers and raising the risk of wildfires, higher-than-normal temperatures also cause health problems ranging from heatstroke and dehydration to cardiovascular stress.
In the United States, local officials said last week that at least 13 people died from an extreme heat wave in Texas and Louisiana.
China issued its highest-level heat alert for northern parts of the country as Beijing baked in temperatures around 40C.
The world has warmed an average of nearly 1.2 C since the mid-1800s, unleashing extreme weather including more intense heatwaves, more severe droughts in some areas and storms made fiercer by rising seas.
