New reports sound the alarm on the cryosphere
Photo caption: Icebergs float in a calm sea under a clear sky at sunrise, with a rocky shoreline in the foreground.
Dramatic changes in the Arctic, including an increase in wildfires, the greening of the Tundra and an increase in winter precipitation, are documented in the US National Oceanic and Atmospheric Administration’s 2024 Arctic Report Card.
It is the latest in a series of scientific findings sounding the alarm about the cryosphere, which has become one of WMO’s top priorities and which has been described as “the canary in the coal mine of the climate system” in WMO’s latest Bulletin.
The cryosphere is the name given to Earth’s snow and ice regions and ranges from ice sheets, glaciers, snow and permafrost to sea ice on the polar oceans.
A separate report, State of the Cryosphere 2024 Lost Ice, Global Damage, from the International Cryosphere Climate Initiative, describes how a combination of melting ice sheets, vanishing glaciers, and thawing permafrost will have rapid, irreversible, and disastrous impacts worldwide.
The report notes a growing scientific consensus that melting Greenland and Antarctic ice sheets, among other factors, may be slowing important ocean currents at both poles, with potentially dire consequences for a much colder northern Europe) and greater sea-level rise along the U.S. East Coast.
“We cannot negotiate with the melting point of ice,” is one of the bottom lines of the report from the International Cryosphere Climate Initiative, which includes scientists from the Intergovernmental Panel on Climate Change (IPCC) and WMO’s Global Cryosphere Watch network.
These new findings corroborate recent WMO State of the Global Climate and State of Global Water Resources reports which also have also highlighted the alarming melting affecting the cryosphere.
Reflecting mounting international concern, 2025 has been declared as the International Year of Glaciers’ Preservation.
Cover of the Arctic Report Card 2024 featuring images of a snowy landscape, a winding river, and two reindeer in a mountainous area.
The Arctic report card contains input from 97 scientists from 11 countries.
It frames the Arctic as in a “new regime,” underscoring that the region today is dramatically changed from even a decade or two ago, with major impacts on local communities, wildlife and ecosystems.
“Yet it must not imply that the Arctic climate has stabilized under human-caused warming. Projections of climate change for the next several decades are clear: change will continue,” write the authors.
The report card includes an Indicator essay on carbon cycling, which notes that permafrost warming trends continue, with Alaska observations showing the 2nd warmest permafrost temperatures on record. The essay also discusses a multidecadal increase in wildfires across North American permafrost regions, with wildfires now an urgent, annual concern for Arctic residents.
“These changes together are pushing the Arctic into uncharted territory,” it comments.
The rapid pace and complexity of Arctic change demand new and strengthened Arctic adaptation and global reductions of fossil fuel pollution, it concludes. It stresses the vital role of indigenous knowledge.
IPCC reports have estimated the amount of carbon stored in permafrost (such as the Arctic Tundra) at about twice the amount in the atmosphere today. However, the IPCC reports present evidence that permafrost is undergoing rapid changes. This is creating challenges for planners, decision-makers and engineers as the structural stability and functional capacities of infrastructure are no longer secure as designed, according to a recent article in the WMO Bulletin.
The Arctic is one of the regions most impacted by climate change. In the last half century, it has warmed at three times the global average, severely impacting its environment, biodiversity, and communities. But changes in the region extend far beyond the Arctic; its effects are felt worldwide.
The Arctic report card also shows that:
Arctic annual surface air temperatures for October 2023-September 2024 ranked second warmest since 1900.
The last nine years are the nine warmest on record in the Arctic.
Summer 2024 across the Arctic was the wettest on record.
Arctic precipitation has shown an increasing trend from 1950 through 2024, with the most pronounced increases occurring in winter.
All 18 of the lowest September minimum ice extents have occurred in the last 18 years.
Arctic Ocean regions that are ice-free in August have been warming at a rate of 0.3°C per decade since 1982.
In addition to the Arctic permafrost, the mountain permafrost constitutes 30% of the global permafrost area, is equally sensitive to climate change and strongly impacts mountain ecosystems and communities. A recent study recently published in Nature Communications notes that during 2013–2022, warming rates at 10 metres depth exceed 1 °C per decade, generally surpassing previous estimates. This is consistent across all sites, depths and time periods for the European mountains.
Permafrost observation sites are geographically unevenly distributed, concentrated across the European mountains and increasingly on the Tibetan Plateau. However, there are only few observations in the Rocky Mountains, the Central Asian mountain ranges, the Himalaya and the Andes.
Maintaining temperature sensors and data loggers in harsh arctic and mountain environments over decades to ensure uninterrupted, robust and comparable records of permafrost temperature poses significant challenges. Standards for site selection and measurement protocols for permafrost temperatures have only recently been elaborated and approved by WMO. Coordinated through the Global Cryosphere Watch and developed with the contribution of a large team of international experts the first global standardization of permafrost monitoring was is being published at the end for 2024 in the WMO Guide for Instruments and Methods of Observation, WMO. No. 8.
Rising temperatures in the atmosphere and ocean around Antarctica are melting the ice sheet. Evidence cited in IPCC reports suggests that if global temperature rise exceeds 2 °C in the long-term, both the Greenland and Antarctic ice sheets may reach tipping points beyond which their melting would become unstoppable even with deep cuts in greenhouse gas emissions.
In addition to sea-level rise, melting of ice sheets has large downstream impacts on, for example, ocean circulation, coastal inundation and food security, exacerbating climate change effects on human societies and the natural world.
There are already signs that some large glaciers in Antarctica have entered a state of irreversible retreat and data from Greenland has shown an increase in surface melt and increases in iceberg calving over the last 30 years, according to the WMO Bulletin’s feature on the cryosphere, written by Rodica Nitu, Michael Sparrow and Stefan Uhlenbrook, WMO Secretariat, and Jeffrey Key (formerly NOAA).
Antarctic sea ice extent reached its lowest monthly value for November, at 10% below average, continuing a series of historically large negative anomalies observed throughout 2023 and 2024, according to data from the European Union’s Coopernicus Climate Change Service and US National Snow and Ice Data Center.
Glacier mass balance is an important climate change indicator. And it is an alarming one.
WMO’s “State of Global Water Resources 2023” and State of the Climate 2024 Update reports show that collectively, the world’s glaciers lost over 600 gigatons of water in 2023. 600 gigatons of water is about 13% of the world’s annual water consumption. It was the largest mass loss in almost 50 years of measurements. Following the year 2022, 2023 was the second consecutive year in which all glaciated regions in the world reported net ice loss.
This underscores a pressing concern: the long-term reduction in water stored as ice will critically affect future water resources for people and ecosystems. To highlight the importance of glaciers, WMO and UNESCO are facilitating the implementation of the International Year of Glaciers’ Preservation in 2025.
