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As reported in the BBC, the Copernicus data suggests that average daily global sea surface temperatures this week are the highest ever recorded, beating a 2016 record.
Prof Helen Findlay, Biological Oceanographer, Plymouth Marine Laboratory, said:
“Temperature is hugely important in regulating biological processes, especially in the ocean where many creatures cannot regulate their own body temperature. These processes impact how species grow, develop, reproduce and interact to make up a healthy ecosystem. As we see more frequent and longer marine heatwaves and overall increases in ocean temperature, some species will be able to cope and some won’t. At an ecosystem level we are still trying to work out what these changes mean – as one species replacing another may seem ok but they can have subtle differences in their life history, which can alter how the ecosystem functions.
“From an initial review, both Copernicus and NOAA data methods are robust and have been used consistently to assess sea surface temperatures over time, both show remarkably similar results, if a fraction of a degree off. The daily “wiggles” will never match because of the subtle differences in the calculations/interpolations/reanalysis. What’s more important is the monthly and yearly patterns: continued year-on-year warming, and to me, what’s so unusual about this second, summer, warming peak that the ocean is experiencing, is that it is much higher than expected for July/August. Data, both NOAA and Copernicus, suggest warmest peaks in March/April before dropping about 0.2 C down to the second lower peak in August. This year, that’s not happened, the second peak appears as big as the first.”
Dr Benjamin Davison, Research Fellow in the School of Earth and Environment, University of Leeds, said:
“As I understand it, the BBC article is based on the near-real time version of the ERA5 dataset. ERA5 is produced by the European Centre for Medium-Range Weather Forecasts (ECMWF) and is the flagship dataset for the Copernicus Climate Change Service (C3S). The purpose of ERA5 is to provide reliable, quality-assured data about atmospheric and ocean conditions globally, every hour since 1940, free of charge. ERA5 is what scientists call a “reanalysis” dataset – a combination of an extremely large set of observations with the laws of physics to provide an accurate reconstruction of past atmospheric and ocean conditions everywhere on the planet. It’s important to note that the 1st August temperature record reported in BBC article is based on the “near-real time” version of ERA5, which is the version of the dataset that is released without delay before being quality checked. In the unlikely event that the near-real time version has a flaw, it will be corrected in a later dataset update – this has only happened once in the history of the dataset. I think it is also important to note that, even if the 2016 record mentioned in the BBC article has not been broken, the current high global sea surface temperatures are nevertheless extremely anomalous, especially for the time of year.
“ERA5 compares exceptionally well to other ocean surface temperature datasets. ERA5 assimilates an extremely large set of ocean surface temperature observations, which we can now monitor with satellites, and the reanalysis approach ensures that the reconstructed temperature is consistent with those observations. Comparisons between ERA5 and measurements of ocean surface temperature acquired from ships show that the differences are about 0.2 degrees Celsius on average.”
Prof Rowan Sutton, Professor of Climate Science, University of Reading and National Centre for Atmospheric Science, said:
“The recent ocean warming is genuinely concerning. The latest sea surface temperature data from Copernicus suggests we may be experiencing not just a record-breaking extreme event but a record-shattering one. And this is not simply for a local measure of temperature, but for a global one, which will have much greater impacts.
“Whilst there are certainly short-term factors, the major long-term cause is without any doubt the accumulation of greenhouse gases in the atmosphere caused by human activities, primarily burning fossil fuels. This is yet another alarm bell that screams out for the most urgent actions to limit future warming and to adapt to the serious changes that are unfolding before our eyes.”
Prof Tim Smyth, Head of Science for Marine Biogeochemistry and Observations, Plymouth Marine Laboratory, said:
“The data we have generated as part of the Western Channel Observatory (WCO; https://www.westernchannelobservatory.org.uk/data.php), providing one of the longest, continuous in situ marine datasets in the world, shows that we are seeing a gradual 0.3 degree per decade increase since the 1960s and that we had a sudden jump in the temperatures in late June, which has since disappeared. We need long-term datasets such as the WCO to be maintained at the frequency at which we are currently sampling then the marine science community can work together to uncover the implications are for all of this in the marine environment, and ultimately society.”
Dr Kaitlin Naughten, an oceanographer from the British Antarctic Survey, said:
“This is reliable data which is based on satellite observations. Other datasets may give slightly different values – for example, NOAA is reporting that last April was still very slightly warmer than now. Regardless of whether we’ve quite broken that record, it’s clear that current sea surface temperatures are exceptionally and unseasonably warm. This is due to a combination of climate change and El Nino, and we can expect temperatures like this to happen more and more frequently in the future. A warm sea surface has wide-ranging implications, especially for complex ecosystems such as coral reefs.”
Prof Daniela Schmidt, Professor of Earth Sciences, University of Bristol, said:
“Copernicus’s excellent but scary compilation data shows what we had feared. The oceans are warming rapidly, unprecedentedly both in area and the deviation from the long term averages. This cannot be El Niño yet as it has only started to develop.
“People tend to forget that when the water gets hot, most organisms in the sea need much more food for their basic function. And what happens if they grow less or calcify less? It will have impacts for their future with fewer offspring or weaker protection by their shells and skeletons.
“We have no time left to deal with this problem in the future. Any further delay will just make the problem so much worse.
“We have so many measures to reduce emissions and increase protection from other stressors. But we are not even willing to stop sewage going into our seas.”
Prof Piers Forster, Professor of Climate Change, Director of the Priestley Centre for Climate Futures, University of Leeds, said:
“The data is very robust, we have satellite data and thermometers on ships and buoys confirming this data. It’s important to be clear whether we’re talking about sea-surface temperatures or ocean temperatures more generally – in this case it’s the surface temperature record that has been broken. The deeper oceans have been warming for decades due to climate change and shifting circulation patterns have likely brought some of that heat to the surface. The ocean heatwave is an immediate threat to some marine life, we are already seeing coral bleaching in Florida as a direct result, and I expect more impacts will surface.”
Data: https://sites.ecmwf.int/data/c3sci/era5-daily/data/
https://cds.climate.copernicus.eu/cdsapp#!/dataset/satellite-sea-surface-temperature?tab=form
BBC story: https://www.bbc.co.uk/news/science-environment-66387537
Declared interests
Prof Helen Findlay: “No conflicts of interest.”
Dr Benjamin Davison: “My research is funded in part by the European Space Agency, who coordinate the delivery of data from satellites within the European Commission’s Copernicus programme. And I make lots of use of the Sentinel satellites, developed by ESA to fulfil the operational needs of the Copernicus programme.”
Prof Rowan Sutton: “I don’t believe I have any relevant interests to declare.”
Dr Kaitlin Naughten: “I have no conflicts of interest.”
Prof Piers Forster: “No conflict of interest.”
For all other experts, no reply to our request for DOIs was received.