The biggest climate records in the last year

The effects of climate change are making themselves known. And these recent climate records are only the beginning, so long as humanity doesn't change course.

1. Hottest month on record

The past year saw a sweltering summer, with July 2023 being declared the hottest month on record, according to the Copernicus Climate Change Service (C3S). The month's average temperature was 62.51 degrees Fahrenheit, six-tenths of a degree higher than the previous record set in 2019, The Associated Press said.

"These records have dire consequences for both people and the planet exposed to ever more frequent and intense extreme events," Burgess said to the AP. The high temperatures are a combination of anthropogenic climate change as well as the El Niño weather phenomenon. "July's record is unlikely to remain isolated this year," as "temperatures are likely to be well above average," said C3S Director Carlo Buontempo.

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"The need to reduce greenhouse gas emissions is more urgent than ever before," Petteri Taalas, a professor and the secretary-general of the World Meteorological Organization, said in a statement. "Climate action is not a luxury but a must."

2. Hottest ocean temperatures

Climate change has also caused unprecedented ocean warming. Along with global air temperatures, water temperatures also hit a record high, almost reaching 100 degrees Fahrenheit in some locations. "From March 2023, the average surface temperature of the global oceans started to shoot further and further above the long-term norm, hitting a new record high in August," said the BBC. "Not only has every single day since 4 May 2023 broken the daily record for the time of year, but on some days the margin has been huge."

"The fact that all this heat is going into the ocean, and in fact, it's warming in some respects even more rapidly than we thought it would, is a cause for great concern," Mike Meredith, a professor from the British Antarctic Survey, said to the BBC. Aquatic species like the emperor penguin are now in danger. "The emperor penguin is a threatened species because of climate change, and the sea-ice and the ocean temperatures are strongly implicated in that," Meredith said. "There have been examples of the sea-ice collapsing before emperor chicks have properly fledged, and there have been mass drowning events."

The water heat is wreaking havoc on marine ecosystems, including coral reefs. "The problem of climate change is that it's happening too quickly for evolution to catch up with it," Dr. Nova Mieszkowska, a marine biologist from the University of Liverpool, said to the BBC. The ocean is the "most accurate thermometer we have for the actual effect of climate change because it's where most of the heat ends up," Zeke Hausfather, a climate scientist at nonprofit research institute Berkeley Earth, said to the New York Times.

3. Lowest Antarctic ice cover

Winter in the Southern Hemisphere is when Antarctic ice is supposed to form. However, in 2023 "growth has been stunted," and the amount of sea ice in the region was "hitting a record low by a wide margin," said The New York Times. "The Antarctic sea ice extent low in 2023 is unprecedented in the satellite record," Liping Zhang, a project scientist at the NOAA's Geophysical Fluid Dynamics Laboratory, said in an email to the Times.

The previous record low was from 2022, but in 2023 the ice level was approximately 1.6 million square kilometers below last year, CNN said. "The Antarctic system has always been highly variable," Ted Scambos, a glaciologist at the University of Colorado Boulder, said to CNN. "This [current] level of variation, though, is so extreme that something radical has changed in the past two years, but especially this year, relative to all previous years going back at least 45 years."

The warmer ocean temperatures are likely mixing into Antarctic waters, preventing ice from forming. Melting ice is a key factor in sea level rise. Ice also serves to reflect back sunlight, helping to regulate global temperatures.

4. Passing 2-degree warming

The United Nations has consistently warned of the dangers of temperatures rising 1.5 degrees Celsius above pre-industrial levels. However, we finally saw a real taste of this temperature. On Nov. 17 of 2023, the planet briefly exceeded two degrees Celsius of warming, the upper maximum of warming cautioned by experts. While exceeding these temperatures by just one day doesn't mean that all is lost, "it's a striking reminder that the climate is moving into uncharted territory," said The Washington Post.

Passing the threshold indicates a shifting baseline. "Our best estimate is that this was the first day when global temperature was more than 2°C above 1850-1900 (or pre-industrial) levels, at 2.06°C," Samantha Burgess, the deputy director of the Copernicus Climate Change Service, said on X. The breach acts as a "canary in the coal mine," Richard Allan, a professor of climate science at the University of Reading, said to CNN. It is "entirely expected that single days will surpass 2 degrees above pre-industrial well before the actual 2 degrees Celsius target is breached over many years."

The temperature is testing the limits of ecosystems and infrastructure alike, putting pressure on power grids and making some regions deadly without access to air conditioners. “Global temperature records are being broken with alarming regularity,” Carlo Buontempo, the director of the Copernicus Climate Change Service, said to The Atlantic. Curbing warming is critical. Greenhouse gas emissions continue to rise every year and further warming is pushing the planet to several tipping points.

5. Highest CO2 emissions

Global carbon dioxide emissions hit a record high this year and will likely cause more extreme weather and warming. According to the Global Carbon Budget, 36.8 billion tons of CO2 were released in 2023, up 1.1% from 2022. "The impacts of climate change are evident all around us, but action to reduce carbon emissions from fossil fuels remains painfully slow," Professor Pierre Friedlingstein, who led the study, said in a press release. India and China mainly drove increases in emissions from coal, oil and gas. Emissions from wildfires were also up in 2023. 

The report also found that approximately half of the released carbon will be absorbed by carbon sinks on the land and in the ocean. "It now looks inevitable we will overshoot the 1.5 degrees Celsius target of the Paris Agreement, and leaders meeting at COP28 will have to agree rapid cuts in fossil fuel emissions even to keep the 2 degrees Celsius target alive," Friedlingstein concluded.

6. Warmest year on record

November 2023 became the sixth straight month to set a heat record and the year is officially the hottest on record. "The last half year has truly been shocking," Burgess said to The Associated Press. "Scientists are running out of adjectives to describe this."

Scientists blamed both climate change and El Niño for the exceedingly warm summer and autumn. In 2023, the planet was at 1.46 degrees Celsius above pre-industrial levels, which is approximately a seventh of a degree warmer than the previous warmest year, 2016. This is also dangerously close to the Paris Agreement's 1.5-degree threshold. Scientists expect that this level of warming is only the beginning if serious changes are not made to curb emissions. "2023 is very likely to be a cool year in the future unless we do something about our dependence on fossil fuels," Burgess said.