Global imprint of climate change on marine life has just been published – the most comprehensive meta-analysis of marine system response to climate change.
The worldwide team of researchers responsible for the work have assembled a database of around 1700 changes in marine life – like shifts in species distribution, phenology etc. 81% of those changes were consistent with the expected effects of climate change, were comparable to changes on land and in many cases were more exaggerated.
This global investigation has revealed the true scale of ocean warming. The comprehensive worldwide study has found that the world’s marine systems are reacting to climate change on a scale greater than scientists previously thought.
The three-year research project, funded by the National Centre for Ecological Analysis and Synthesis of California, shows that complete shifts are widespread in a number of marine biological responses, including the distribution of species and phenology – the timing of nature’s calendar. It also shows that these shifts are comparable to or greater than those observed on land.
The report, Global imprint of climate change on marine life, is published in this month’s Nature Climate Change and will be used by the Intergovernmental Panel for Climate Change. It was led by the University of Queensland and included the Scottish Association for Marine Science (SAMS) in Argyll, among 17 institutions across the world.
One of the report’s lead authors, Professor Mike Burrows in the Department of Ecology at SAMS, said the study was ‘the most comprehensive review of published reports of the effects of climate change in the sea.’
Professor Burrows says: ‘Most of the effects we saw were as expected from changes in climate. So, most shifts in the distributions of, say, fishes and corals, were towards the poles, and most events in springtime, like spawning, were earlier. Despite the increase in temperatures in the ocean being smaller than on land, the changes in ecology were every bit as evident in the sea, and sometimes even bigger.’
The team worked through hundreds of published papers to compile a global database of observed marine biological responses to regional and global climate change.
Professor Camille Parmesan at the University of Texas explained how one possible difficulty with this new study being perceived as novel and unique is that ‘the basic messages are so similar to those from previous global analyses.
‘I think this is the coolest aspect of the results. Basically, here’s a totally different system with its own unique set of complexities and subtleties, yet the over-arching impacts of recent climate change in the oceans tell a very similar story to that of species on land. The big picture remains the same – an over-whelming response of species’ shifting where and when they live in an attempt to track a shifting climate.’
The research team was organised and led by Elvira Poloczanska and Anthony Richardson who are credited with achieving a report that is ‘truly looking at biological impacts from a new and unique perspective’. They made this possible by drawing together a global-spanning international team of experts.
Among numerous parallel observations, the report shows that over a 40-year period the global average of species displacement was 75 kilometres, which is up to ten times the figure for terrestrial displacement. The most noticeable effects were seen in phytoplankton, zooplankton and bony fish.
Mike Burrows says: ‘Some of the biggest shifts in relation to changing climate were in the North Sea, with some fish and plankton shifting northwards at up to 200km per decade over the last 50 years’.
The researchers also found that spring phenology in the oceans has advanced by more than four days, nearly twice as fast as on land. The strength of response varied among species, with the greatest advancement of up to 11 days in invertebrate zooplankton and larval bony fish.
Other evidence indicating that climate change is the primary driver behind the observed changes was the opposing responses within a community of warm-water and cold-water species.
In total, 83% of all the observations, whether for distribution, phenology, community composition, abundance, or demography, across different populations and ocean basins, were consistent with the expected impacts of climate change.
Mr Burrows says: ‘The effects of climate change on marine life might not be immediately visible, but when, for example, fish we are used to catching in Scotland, like mackerel, shift away from our waters in search of cooler climes, the economic and political consequences can be severe’.