Climate Crisis Deepens As 2024 Breaks Global Heat Records

New research confirms that 2024 was the hottest year on record, pushing Earth past the critical 1.5°C warming threshold. Scientists warn that this could mark the beginning of a prolonged period of elevated temperatures, threatening ecosystems, economies, and societies worldwide. While some progress has been made in reducing emissions, urgent and decisive action is needed to reverse the trend before it’s too late

Earth is crossing the critical threshold of 1.5°C of global warming, according to two major global studies. These studies suggest that the planet's climate has likely entered a new and alarming phase. Under the landmark 2015 Paris Agreement on climate change, humanity aims to reduce greenhouse gas emissions and limit planetary heating to no more than 1.5°C above the pre-industrial average. In 2024, Earth's temperatures surpassed this limit. However, this alone is not enough to declare that the Paris threshold has been permanently crossed, as the agreement measures temperature goals over several decades rather than short-term fluctuations beyond the 1.5°C mark.

The two newly released studies, however, take a different approach. Both examined historical climate data to determine whether recent extreme temperatures indicate that a future long-term warming threshold has been breached. Alarmingly, the answer was yes. The researchers assert that the record-breaking heat of 2024 suggests Earth is passing the 1.5°C limit, beyond which scientists predict catastrophic harm to the natural systems that sustain life.

Climate organisations worldwide agree that last year was the hottest on record. The global average temperature in 2024 was approximately 1.6°C above late 19th-century levels, before humans began burning fossil fuels on a large scale. Earth has also recently experienced individual days and months surpassing the 1.5°C warming mark.

However, global temperatures fluctuate from year to year. While the 2024 temperature spike was primarily driven by climate change, it was also influenced by a natural El Niño pattern earlier in the year. That pattern has since dissipated, and 2025 is expected to be slightly cooler. Because of these year-to-year variations, climate scientists do not view a single year exceeding the 1.5°C mark as an outright failure to meet the Paris Agreement.

Nonetheless, the new studies published in ‘Nature Climate Change’ suggest that even a single month or year at 1.5°C global warming could indicate that Earth is entering a long-term breach of this critical threshold.

The studies were conducted independently by researchers in Europe and Canada, both addressing the same fundamental question: does a single year above 1.5°C warming signal that we are permanently crossing the Paris Agreement threshold?

Both studies used historical climate observations and model simulations to analyse the data, though with slightly different methodologies. The European study examined historical warming trends and found that once Earth's average temperature reached a certain threshold, the subsequent 20-year period also remained at that level. This pattern suggests that since Earth reached 1.5°C warming last year, we may have entered a prolonged 20-year period of similar warming levels.

The Canadian study analysed month-to-month data and found that June 2024 marked the 12th consecutive month of temperatures exceeding the 1.5°C threshold. According to their findings, a continuous 12-month period above a climate threshold strongly indicates that the threshold will persist in the long term.

Both studies also highlight that even with immediate and aggressive emissions reductions, Earth is still likely to continue crossing the 1.5°C threshold.

Given these findings, humanity's next steps are crucial. For decades, climate scientists have warned that burning fossil fuels for energy releases carbon dioxide and other greenhouse gases that warm the planet. However, global greenhouse gas emissions have continued to rise. Since the Intergovernmental Panel on Climate Change (IPCC) released its first report in 1990, annual global carbon dioxide emissions have increased by approximately 50per cent.

Put simply, we are not even moving in the right direction, let alone at the pace required. Science shows that greenhouse gas emissions must reach net-zero to halt global warming. Even then, certain climate changes, especially Regional Ocean warming, are already locked in an irreversible for centuries.

If Earth has indeed already crossed the 1.5°C mark and humanity wishes to return below this threshold, we must cool the planet by achieving "net-negative emissions"—removing more greenhouse gases from the atmosphere than we emit. This, however, would be an extremely challenging task.

The devastating effects of climate change are already evident worldwide, and future generations will face even greater challenges. Australia, for instance, has already experienced an average warming of 1.5°C since 1910. Unique ecosystems such as the Great Barrier Reef are suffering due to rising temperatures. Our oceans are hotter, sea levels are rising, and coastlines are under threat. Extreme weather events, including bushfires and heatwaves, are becoming more frequent and severe, placing immense pressure on nature, society, and the economy.

Amid this bleak outlook, there are signs of progress. Globally, renewable electricity generation is expanding, and fossil fuel consumption has declined in several countries. Technological advancements are slowing emissions growth in highly polluting industries such as aviation and construction. However, much more action is needed.

These studies serve as a sobering reminder of how much more needs to be done to combat climate change. They emphasise the urgent need to adapt to further global warming. As part of this response, wealthier nations must provide greater support to poorer countries, which will suffer the most severe climate impacts. While some progress has been made in this regard, significantly more effort is required.

Additionally, a major transformation is necessary to decarbonize our societies and economies. There is still hope, but we must act swiftly. Delaying action will only worsen the crisis, increasing the damage humanity inflicts on the planet.

(Andrew King, Associate Professor in Climate Science Geography, Earth and Atmospheric Sciences and Liam Cassidy is a researcher, The University of Melbourne)