Nearly 35 years after global warming became increasingly prominent in the international public debate, Planet Earth experienced its warmest calendar year on record in 2023, based on recorded data dating back to 1850. Last year was the year when many climate records tumbled, and for the worse. In fact, 2023 was the year when the average global temperature settled very close to the 1.5°C threshold, a key benchmark in climate change tracking.

The year witnessed close to the warmest average air temperatures, two warmest months on record, unusually and persistently high global average sea surface temperatures (SSTs), marine heat waves, record low extents for the Antarctic sea ice, and extreme weather events including heat waves, floods, droughts and wildfires.

Before 2023, the global average temperature was recorded highest in 2016. Last year, it settled at 14.98°C, 0.17°C higher than recorded for 2016.

All this has been detailed in the 2023 annual climate summary, ‘Global Climate Highlights 2023’, released by the Copernicus Climate Change Service (C3S). The Copernicus Climate Change Service is part of the European Centre for Medium-Range Weather Forecasts, an agency of the European Union.

For a regular civilian, climate change and global warming become concerns when they start to directly impact them. Otherwise, these are terms mostly confined to books and news headlines. But in 2023, a huge population around the globe were impacted by extreme weather events. And the forecasts for 2024 are worse. It has been projected that the ongoing calendar year will be warmer and another record-breaking year.

2023 – a year of extremes

The report states that the global average temperature in 2023 was 1.48°C higher than the 1850-1900 pre-industrial level. This almost breaches the 1.5°C threshold which even world leaders have agreed to as the limit for human-induced global warming. But importantly, they had agreed to limit global warming to 1.5°C by the end of this century, i.e. 2100, not by the middle of the 21st century or earlier. However, it is also significant to note here that recording a global average temperature 1.5°C higher than the 1850-1900 pre-industrial level for a year or two does not necessarily mean that the significant threshold of global warming has been breached. For that to happen, such extreme temperatures would have to be consistently recorded as the average temperature of the planet over a twenty or thirty-year period, which is typically used to define climate.

The report further states that 2023 was also 0.60°C warmer than the 1991-2020 average. And it is possible that a 12-month period ending in January or February this year could actually see global-average temperature settle 1.5°C above the pre-industrial level.

Another significant (and worrying) data is that temperatures were recorded 1°C above the pre-industrial level every single day in 2023, the very first such instance. And on two days during the year, the significant threshold of even 2°C was breached. This has happened for the first time in recorded history.

“Close to 50% of days were more than 1.5°C warmer than the 1850-1900 level. Two days were more than 2°C warmer than 1850-1900, the first time the 2°C level has been exceeded,” the report released on January 9 states.

In comparison, a little more than 20% of days in 2016 - the previous warmest year on record – recorded temperatures 1.5°C higher than the 1850-1900 pre-industrial levels.

There are many more horrific milestones that 2023 witnessed, if we consider climate change and global warming an existential threat to humanity.

Why is 1.5°C threshold important?

Before moving to the other aspects of the report, it is important to understand the 1.5°C threshold. This threshold has been mentioned in the Paris Agreement that was adopted on December 12, 2015 by nations at the UN Climate Change Conference (COP21) in the capital of France. The Agreement took effect on November 4, 2016 and is a legally binding global treaty on climate change.

The treaty lays down that the increase in the global average temperature should be limited to well below 2°C above pre-industrial levels. Further, efforts should be made to restrict the temperature rise to 1.5°C above pre-industrial levels.

As mentioned above, in the years after the Paris Agreement was reached and extreme weather events were experienced, global leaders have talked about the need to restrict global warming to 1.5°C by the end of this century.

This is also because the United Nations’ Intergovernmental Panel on Climate Change has stated that the world risks experiencing far worse climate change impacts in the form of frequent and severe droughts, heat waves and rainfall if the 1.5°C threshold is breached.

It has also been stated that if global warming has to be restricted to the 1.5°C threshold, emissions of greenhouse gas have to peak before 2025 and then come down by at least 43% by the year 2030.

Records after records broken

Getting back to the events of 2023, starting June, every month last year was warmer than the corresponding month in any previous year. In fact, July and August turned out to be the warmest two months on record ever since data started to be maintained.

Further, the average air temperatures in 2023 were recorded to be the warmest ever, or at least close to the warmest, states the report. Such temperatures were recorded in large areas over all ocean basins and all continents, barring Australia.

“Almost all land areas experienced above-average temperatures in 2023. Marine air temperatures were also the warmest on record for several regions in 2023,” states the alarming Copernicus report.

Scientists who put together the report mentioned that the year-to-year jump in global average temperature from 2022 to 2023 was sort of unprecedented in terms of range. All this happened in the middle of a transition from three years of La Ni?a weather phenomenon in 2020–2022 to El Ni?o in 2023. While El Ni?o conditions also had their contribution to the warmth experienced in 2023, the phenomenon was not as strong last year as was experienced earlier in 2015 and 1997.

For the unversed, El Ni?o and La Ni?a are climate patterns in the Pacific Ocean that cause significant fluctuations in our planet’s climate system and impact global weather.

Away from the land, weather agencies also recorded persistent and unusually high global-average sea surface temperatures. These touched record highs from April to December. These were accompanied by marine heat waves across the planet.

Why this is significant is explained in Copernicus’s Global Climate Highlights 2023 report: “Typically, SSTs reach their highest level for the year in March and then begin to fall, before a slight increase again during July and August. …data show this year to be atypical in that, after an initial sharp rise in early March and only a slight dip during April and May, global average SSTs have continued to rise to reach the highest value in the ERA5 dataset of 21.02°C on 23 and 24 August. This is higher than the previous record of 20.95°C, set in March 2016. In fact, every day from 31 July to 31 August this year has been warmer than the previous record set in March 2016.”

More worrying signs

The extreme weather-related events also had indirect impacts on the planet. For example, a 30% jump was recorded in the estimated global wildfire carbon emissions last year compared to the previous year, i.e. 2022. The persistent wildfires in Canada contributed a major chunk to these emissions.

In Antarctica, sea ice witnessed its record low extents over 8 months compared to the corresponding months in previous years. February 2023 recorded all-time minima for both the daily and monthly extents.

In the north as well, the Arctic sea ice extent was recorded to be among the fourth lowest for its annual peak in March. The annual minimum in September was also the sixth-lowest, as per satellite records.

Carbon dioxide and methane in the atmosphere also touched their record levels last year, reaching 419 ppm and 1902 ppb, respectively.

Will 2024 be worse? Possibly yes

2024, according to a recently released forecast, could end up being warmer than 2023. In fact, there is a reasonable probability that the calendar year could witness an average annual temperature in breach of 1.5°C threshold. The UK Met Office has forecast 2024 to be a further record-breaking year as far as global temperatures are concerned.

The UK’s Met Office on its website quotes Professor Tim Osborn, of the University of East Anglia’s Climatic Research Unit, in a press report: “Twenty-five years ago, 1998 was a record-breaking year for global average temperature. But last year’s global temperature was 0.5 °C warmer than 1998, providing further evidence that our planet is warming on average by 0.2 °C per decade.

“At the current rate of human-induced warming, 2023’s record-breaking values will in time be considered to be cool in comparison with what projections of our future climate suggest.”

Certainly, the projections are worrying and time is running out before we cross the threshold where irreversible damage would have been caused to our planet and its climate system.