An alarming streak of exceptional global temperatures is set to continue, with 2025 forecast to be the second or third warmest year since record-keeping began 176 years ago, according to a new report from the United Nations’ World Meteorological Organization (WMO). This places it among the record-breaking heat of 2023 and 2024, continuing a trend that has seen the last 11 years (2015–2025) register as the warmest ever observed. The persistence of this extreme heat underscores the escalating climate crisis and the immense challenge of limiting global warming to the targets set by international agreements.
The WMO’s “State of the Global Climate Update” report, released ahead of the COP30 climate summit in Brazil, provides a stark assessment of the planet’s condition. It confirms that the primary drivers of this warming trend are record-high concentrations of greenhouse gases in the atmosphere, which continue to trap heat and warm the planet. While 2025 is not expected to surpass 2024 as the absolute hottest year, its ranking continues a pattern of relentless warming that scientists have unequivocally attributed to human activities, primarily the burning of fossil fuels. This sustained heating has profound implications, causing cascading impacts on global economies, deepening inequality, and threatening irreversible damage to ecosystems.
A Decade of Unprecedented Heat
The WMO report highlights that every year from 2015 to 2025 has been among the 11 warmest on record. This consistent run of record temperatures demonstrates a clear long-term warming trend. During the first eight months of 2025, the mean near-surface temperature was approximately 1.42°C above the pre-industrial average. This is perilously close to the 1.5°C limit that the 2015 Paris climate accords aimed to stay below.
The accumulation of heat is not confined to the atmosphere. Ocean heat content also reached record levels in 2024 and continued to rise in 2025. This oceanic warming has global consequences, influencing weather patterns and contributing to sea-level rise. Other critical indicators of climate change, such as the retreat of glaciers and sea ice, also persisted. In 2025, Arctic sea ice extent after the winter freeze was the lowest on record, while Antarctic sea ice remained well below average.
The Role of Greenhouse Gases
The principal cause of the sustained rise in global temperatures is the increasing concentration of greenhouse gases in the atmosphere. Human activities, particularly the combustion of fossil fuels like coal, oil, and gas for energy, are the largest source of these emissions, accounting for over 75% of the total. These gases blanket the Earth, trapping heat from the sun and causing the planet to warm at a rate faster than any point in recorded history.
Drivers of Emissions
Several sectors are major contributors to greenhouse gas emissions. The generation of electricity and heat through burning fossil fuels is a primary source. Manufacturing and industry also produce significant emissions, not only from energy use but also from chemical processes involved in making products like cement, steel, and plastics. Furthermore, deforestation and certain agricultural practices release large amounts of carbon dioxide and other greenhouse gases like methane into the atmosphere.
Climate Patterns and Future Outlook
Natural climate phenomena also play a role in year-to-year temperature variations. The record heat of 2023 and 2024 was amplified by a strong El Niño event, a weather pattern characterized by warmer-than-average sea surface temperatures in the tropical Pacific Ocean. In 2025, the Pacific transitioned to neutral or La Niña conditions, which typically have a slight cooling effect on global temperatures. For every 1°C of cooling during a La Niña, global average temperatures can drop by about 0.07°C. Despite this, the baseline temperature is now so high due to human-caused warming that 2025 will still be one of the hottest years ever recorded.
The Challenge of the 1.5°C Target
The persistent high temperatures have made the goal of limiting global warming to 1.5°C above pre-industrial levels increasingly difficult to achieve. WMO Secretary-General Celeste Saulo stated that the unprecedented streak of high temperatures and record greenhouse gas levels makes it “virtually impossible to limit global warming to 1.5°C in the next few years without temporarily overshooting this target.” UN Secretary-General António Guterres echoed this concern, calling the failure to limit the temperature rise a “moral failure” and emphasizing the severe consequences of each year the world spends above the 1.5°C threshold.
A Path Forward
Despite the dire warnings, climate scientists and international leaders maintain that it is still possible to return temperatures to below the 1.5°C target by the end of the century. However, this would require immediate, rapid, and large-scale action to reduce greenhouse gas emissions across all sectors of the global economy. The upcoming COP30 summit in Brazil is seen as a critical opportunity for nations to strengthen their commitments and accelerate the transition away from fossil fuels.
