2024 on track to become the warmest year on record, says WMO

2024 is on track to be the warmest year on record after an extended streak of exceptionally high monthly global mean temperatures, the World Meteorological Organization (WMO) has said.

2015-2024 will be the warmest decade on record with the loss of ice from glaciers, sea-level rise and ocean heating accelerating global warming. “Extreme weather is wreaking havoc on communities and economies across the world,” the WMO said.

The WMO “State of the Climate 2024 Update” report points out that the ambitions of the Paris Agreement are in great peril. “Climate catastrophe is hammering health, widening inequalities, harming sustainable development and rocking the foundations of peace. The vulnerable are hardest hit,” said UN Secretary-General António Guterres.

Red alert issued

The report was issued on the first day (Monday) of the UN Climate Change Conference, COP29, in Baku, Azerbaijan.  The global climate organisation’s “State of the Climate 2024 Update” issued a red alert at the pace of climate change, turbo-charged by ever-increasing greenhouse gas levels in the atmosphere.  “The record-breaking rainfall and flooding, rapidly intensifying tropical cyclones, deadly heat, relentless drought and raging wildfires that we have seen in different parts of the world this year are unfortunately our new reality and a foretaste of our future,” said WMO Secretary-General Celeste Saulo.

The January-September 2024 global mean surface air temperature was 1.54°C (with a margin of uncertainty of ±0.13°C) above the pre-industrial average, boosted by a warming El Niño event, according to an analysis of six international datasets used by WMO.

The update said the global mean temperature in 2024 is on track to outstrip the temperature even of 2023, the current warmest year. For 16 consecutive months (June 2023 to September 2024), the global mean temperature likely exceeded anything recorded before, and often by a wide margin, according to WMO’s consolidated analysis of the datasets. “As monthly and annual warming temporarily surpass 1.5°C, it is important to emphasise that this does not mean that we have failed to meet Paris Agreement goal to keep the long-term global average surface temperature increase to well below 2°C above pre-industrial levels and pursue efforts to limit the warming to 1.5°C,” said Saulo.

As global warming continues, there is an urgent and unavoidable need for careful tracking, monitoring and communication with regard to where the warming is relative to the long-term temperature goal of the Paris Agreement, to help policymakers in their deliberations, said the WMO.  To support this, WMO has established an international team of experts, and the initial indication is that long-term global warming is currently likely to be about 1.3°C compared to the 1850-1900 baseline.

Greenhouse gases

Greenhouse gases reached record observed levels in 2023. Real-time data indicate that they continued to rise in 2024. The atmospheric concentration of carbon dioxide (CO₂) has increased from around 278 ppm in 1750 to 420 ppm in 2023, an increase of 51 per cent. This traps heat and causes temperatures to rise.

Ocean heat content in 2023 was the highest on record and preliminary data show 2024 has continued at comparable levels. Ocean warming rates show a particularly strong increase in the past two decades. From 2005 to 2023, the ocean absorbed approximately 3.1 million terawatt-hours (TWh) of heat each year. This is more than 18 times the world’s energy consumption in 2023.

About 90 per cent of the energy that has accumulated in the Earth system is stored in the ocean. Therefore, ocean warming is expected to continue – a change that is irreversible on centennial to millennial timescales, the update said.

Sea level rise is accelerating because of the thermal expansion of warmer waters and melting glaciers and ice sheets. From 2014-2023, global mean sea level rose at a rate of 4.77 mm per year, more than double the rate between 1993 and 2002. The El Niño effect meant it grew even more rapidly in 2023.  Preliminary 2024 data show that, with the decline of El Niño, it has fallen back to levels consistent with the rising trend from 2014 to 2022. 

The WMO Secretary-General said, “... it is essential to recognise that every fraction of a degree of warming matters. Whether it is at a level below or above 1.5°C of warming, every additional increment of global warming increases climate extremes, impacts and risks.”

“We urgently need to reduce greenhouse gas emissions and strengthen our monitoring and understanding of our changing climate. We need to step up support for climate change adaptation through climate information services and early warnings for all,” she said.