The year 2023 was the hottest year on record for the Earth so far, surpassing the previous record set in 2016 by a significant margin, according to the World Meteorological Organization (WMO) report. The report indicates that each month between June and December of the past year set new records for warmth, with July and August being the hottest months in history.
The WMO utilizes various indicators from around the world to measure global temperatures. These indicators reveal that, over the past 12 months, there has been an increase of 1.45 degrees Celsius compared to the pre-industrial era (1850–1900). Some scientists, including former NASA climate scientist James Hansen, predict that 2024 could be the first year when the global average temperature surpasses the 1.5°C threshold, a level that environmental experts have long warned about.
Environmental scientists express concern that unless the Earth remains consistently below 1.5°C, the expected increase in warming beyond control cannot be ruled out. In 2024, the Earth is projected to face the challenge of reaching 1.5 degrees Celsius above pre-industrial levels for the first time. WMO Secretary-General Petteri Taalas commented on the situation, stating that climate change is the most significant issue facing humanity, affecting the entire world and particularly vulnerable populations. Immediate and substantial actions, along with a rapid transition to renewable energy, are necessary to mitigate the intensifying impacts of long-term climate change.
United Nations Secretary-General Antonio Guterres remarked on the WMO's global climate report, stating that the Earth is slipping due to human activities. The increase observed in global temperatures in 2023 is an example of the potential devastation resulting from the absence of measures to control climate change. Although it is still possible to mitigate the worst effects of climate change, urgent and determined efforts are needed to limit the increase in global temperatures to 1.5 degrees Celsius. Since 1980, each decade has been hotter than the preceding one, with the past nine years (2014–2023) being the warmest on record.
The long-term consequences of global climate monitoring continually demonstrate the single indicator of climate change. Increased concentrations of greenhouse gases, rising sea levels, temperature elevation, acidification, reduced sea ice, and widespread glacier melt are among the other indicators. The potential impact of the increase in temperature to 1.5 degrees Celsius in 2024 on people and nature remains to be seen. Scientists suggest that coral reefs are under threat due to warm water, and ecosystems like tropical marine ecosystems are at risk in the face of complex environmental challenges.
Marine experts Ideal Dixon and Maria Baker (Ladies University) and naturalist Peter Collins (NASA), along with Scott F. Heron (James Cook University), state that corals have adapted to thrive within a specific temperature range. Therefore, when the sea temperature remains excessively warm for extended periods, corals can lose their color and ultimately die. Climate change has already increased the frequency of marine heatwaves, according to Dixon's research. In a world where the temperature exceeds 1.5 degrees Celsius, 99 percent of coral reefs will face intolerable heat, posing a threat to the sustenance and livelihoods of approximately one billion people.
Coral reefs are a critical indicator of the impacts of climate change on the natural world. According to Alex Paget, a biodiversity scientist at University College London, as global temperatures continue to rise toward a 2-degree Celsius increase, the damage to coral reefs will become more evident and pronounced. As per their analysis, limiting global warming to 1.5 degrees Celsius can mitigate the sudden loss of 15 percent of coral reefs within their current geographical boundaries. However, the risk doubles and reaches 30 percent at our current rate of warming (2.5 degrees).
Exceeding the 1.5-degree Celsius threshold is highly dangerous for humanity because it impairs the body's ability to cool down, as highlighted by environmental scientists Tom Matthews (Loughborough University) and Colin Raymond (California Institute of Technology). To avoid these catastrophic scenarios, they emphasize the urgent need to eliminate the emission of greenhouse gases that contribute to warming the Earth—namely, coal, oil, and gas, which account for 80 percent of global energy usage.
The scientists, Chris Smith (University of Leeds) and Robin Lamboll (Imperial College London), suggest that to achieve a 50/50 chance of limiting global warming to 1.5 degrees Celsius, we must only emit 250 gigatons (billion metric tons) of carbon dioxide. They argue that this effective approach could bring the world to net zero in just six years.