Debunking false claims about sea ice
Social media is regularly used to propagate false claims misinterpreting scientific data and implying that there is evidence against human-caused climate change. Polar regions are closely monitored and the satellite data that are used to monitor them are often subject to misinterpretations to question climate-change.
Misinterpretation of satellite data
Climate data records documenting changes in the polar regions are regularly targeted by skeptics in attempts to divert the public opinion and propagate false conclusions. A recurrent claim is that sea ice concentration in the Arctic is increasing while on the contrary the long-term trend of shrinking ice is well-documented.
Earlier this year, Thomas Lavergne, OSI SAF Sea Ice expert at Norwegian Meteorological institute was called by the international press agency AFP fact checking service to comment. In an other article, National Snow and Ice Data Center (NSIDC) Director, Mark Serreze told AFP the data shown in post is correct, but was taken out of context. Let's have a closer at Sea Ice data used in publications shared on social media.
"Article misinterprets satellite data to claim sea ice at 30-year high"
This news article checks the facts behind a social media post claiming that satellite data shows Arctic sea ice is at a 30-year high, implying that this is evidence against human-caused climate change. OSI SAF data used in this social media publication were misinterpreted. The long-term trend of shrinking ice is well-documented. Read the full story here.
"Facebook post misinterprets data to suggest Arctic ice is not declining"
A Facebook post says satellite images showing Arctic sea ice in May at two points over a 33-year timespan are evidence the ice is not shrinking due to human-caused climate change. The head of the National Snow and Ice Data Center (NSIDC) that produced the data said it had been misinterpreted: the broader overall trend of declining sea ice is widely documented. Read the full story here.
In the Arctic, the sea-ice cover (area and extent) is declining in all months. This reduction in sea ice extent and area does however not happen at a constant speed, there are year-to-year variations: some years will have more sea ice than expected from the trend, some years will have less.
A common misleading presentation of sea ice data record comes from cherry-picking years to manipulate the trend.
OSI SAF climate data records show a decline in Arctic sea ice
May 1989, for example, saw less Arctic ice than average, and May 2022 had more than average for those periods. To measure the impact of global warming on sea ice, we calculate the percentage change in its extent and volume compared to the average for a reference period of 30 years -- in this case, 1981 to 2010. Cherry-picking two years gives a wrong interpretation of the trend measured in the climate data record of OSI SAF sea-ice data.
The trend over the last 40 years is clear : May trend : -2.5%/decade, September trend: -11,5%/decade. The decline is more pronounced in summer (September) than in winter (March) as shown by several satellite products that cover the last 40 years.
NSIDC and OSI SAF satellite data records
NSIDC and OSI SAF satellite data records show a general decline in sea ice starting in 1979. There is day-to-day, month-to-month and year-to-year variability in the Arctic sea ice cover as in many other climate variables. Therefore, one cannot infer much, if anything, from the comparison of two daily sea ice maps 33 years apart. Changes in our climate can only be assessed based on long continuous time series.
If you want to read more about climate fact checks by AFP you can visit https://factcheck.afp.com/.
Other highly recommended sources of information to learn more about Arctic Sea Ice :
- To have the latest updates about OSI SAF Sea Ice Indicators visit https://osisaf-hl.met.no/.
- Read the latest news about Arctic Sea Ice from NSIDC visit https://nsidc.org/arcticseaicenews/.
- Read the latest Copernicus Climate Change Service / European State of the Climate report about Sea Ice : https://climate.copernicus.eu/esotc/2021/arctic-sea-ice.
- Read the latest Copernicus Marine Service / Ocean State Report : https://marine.copernicus.eu/access-data/ocean-state-report.