A comprehensive annual climate overview, on which CPOM researchers were co-authors, has been released by the Copernicus Climate Change Service (C3S) containing invaluable insight into the state of our climate in 2019 to help build up a long-term picture of how it is changing.
- 2019 was the warmest year on record for Europe
- 11 of the 12 warmest years occurred since 2000 in Europe
- Long-term view shows clear warming trend across the last four decades
- European Arctic relatively colder than in recent years but summer heatwave causes record surface ice melting in Greenland
Professor Andrew Shepherd, CPOM Director and a contributor to the report, comments on the report in numerous media articles:
RTE: ‘Andrew Shepherd, director of the University of Leeds’ Centre for Polar Observation and Modelling, said C3S’s data was all the more worrying as it foreshadowed accelerated melting of the Greenland Ice Sheet.
“We can’t avoid the rapid changes in climate that are happening around our planet, even if they occur miles away in the polar regions, because they affect our weather today and will affect our coastlines in the future,” he said.’
The TImes: “The warming Europe has experienced over the past year is part of a wider pattern that has led to record loss of ice from Greenland, and this has in turn driven up sea levels around the planet faster than expected”.
The Greenland Ice Sheet section of the report provides further information: “The European State of the Climate 2019, compiled by C3S from a range of data sources with contributions from key players in the field of climate science, offers a complete overview of annual and seasonal conditions across the whole of Europe and the European Arctic which are compared with the long-term average. This gives a clear picture for policymakers, planners, industry sectors, businesses and individuals to help put in place mitigation and adaptation measures against the effect of climate change.
- In Summer 2019, the Greenland ice sheet experienced record melting.
- Model estimates indicate that as a result, the surface mass balance anomaly was the lowest on record, at 320 gigatonnes (Gt) below the 1981-2010 average.
During summer 2019, warm air reached the Greenland ice sheet and persistent anticyclonic conditions trapped it there for an extended period. The result was widespread surface melting across the entire ice sheet, with satellite observations showing that 95.8% of the ice sheet surface experienced melting at least once during the summer months. The figure below shows the daily extent of the melt for all of Greenland, with a large peak in late July and early August.
The Greenland ice sheet gains mass through snowfall during winter and loses mass through surface melting during late spring and summer (usually from May through to the end of August). The difference between the accumulation and melting of snow and ice is called the surface mass balance. Surface mass balance is calculated annually for 1 September to 31 August, based on models that simulate the different surface processes. It does not take into account ice losses from icebergs calving or glacier ice melting at the margins of the ice sheet due to warm ocean temperatures. Generally, the surface mass balance is positive.
The 2019 surface mass balance was the lowest since the start of the record in 1949, with a negative anomaly of 320 gigatonnes (Gt) per year compared to the 1981-2010 average. Below-average snowfall and an early start to the melting season (mid-April) resulted in the early exposure of bare ice. This further enhanced melting, as bare ice reflects less solar energy than fresh snow, in what is termed melt-albedo feedback.
Between 1992 and 2018, surface mass balance accounted for just over half of the total ice loss (50.3%) in Greenland. However, surface mass balance is highly variable from year to year. While 2019 saw a record low surface mass balance year, the two previous years were above the 1981-2010 average by 80 and 150 Gt, respectively. The remaining ice losses are due to discharge and are measured using satellites; discharge losses have progressively increased from -52 ± 44 Gt/yr for 19921997 to -75 ± 21 Gt/yr for 2012-2017. As the discharge data are not yet available for 2019, it is not possible at this stage to make the full ice loss assessment for 2019.
Read more about how ice sheets are changing in the Ice Sheet indicator.”
Carlo Buontempo, Director of the Copernicus Climate change Service (C3S), comments: “It is now more vital than ever before that everyone has access to this information to help us understand the longer-term implications of climate change and what organisations and individuals can do to reduce its effects. One exceptional warm year does not constitute a warming trend, but to have detailed information from our operational service, that covers many different aspects of our climate, we are able to connect the dots to learn more about how it is changing.”