| Climate change is subtly altering
average yearly and seasonal temperatures on land and water and
looks set to have a significant impact on Northern Ireland’s
coastal ecology, according to Dr David Schoeman, a University
of Ulster marine scientist and co-author of an important international
study into ocean warming.
Having mapped the spread northwards of slowly rising average
sea and land temperatures, the study projects that, over the
next 50 years, some marine life and land-based plant and animal
species will relocate to “fresh comfort zones” around the
north coast - that is, to areas with temperatures they need
for survival.
The study, which uses global temperature records to investigate
the likely climate-change responses of marine life in terms
of adapting and relocating, is published
in the authoritative journal, Science.
Experts from the UK, USA, Australia, Spain, Germany and Denmark
who compiled the study are calling for greater understanding
of humankind’s dependence on marine biodiversity and the need
for more research funding to provide the knowledge on which
long-term response-planning can be based.
Since 1960, land temperatures have risen by 1.2ºC, while
sea temperatures have increased by just one-third of that.
The report suggests that, while on paper the increase in
temperatures seems small, there have already been ecological
repercussions. Temperature bands are moving polewards, spring
temperatures are arriving earlier and autumn temperatures
are coming later. Other side-effects could be even more profound
as global greenhouse gas emissions increase.
Dr Schoeman said - “Our study has very significant global,
national and local dimensions - from flagging up concern about
the future of coral life in parts of the western Pacific Ocean,
to heightening awareness about the spreading effects of warming
around our own coastline.”
The work was led by Dr Michael Burrows, from the Scottish
Association for Marine Science and Dr Schoeman, from the Environmental
Sciences Research Institute at Ulster’s Coleraine campus and
was funded by the US National Science Foundation via the US
National Center for Ecological Analysis and Synthesis, University
of California Santa Barbara.
The study shows that typical spring and autumn temperatures
in the ocean are changing more rapidly than they are on land.
Regional variations mean that, in many areas, marine organisms
must respond much more rapidly to changing climate than their
counterparts on land. The study examined the speed and direction
at which land and marine life must travel to remain in their
preferred temperatures. Whereas fish can swim several
kilometres, other bio-organisms such as coral are static.
Dr Schoeman said - “Corals are critically important for marine
biodiversity because about a quarter of the species of fish
that we know about in the ocean are associated with corals,
as are many other forms of marine life.”
The world’s largest concentrations of corals are found in
areas of the Pacific near Indonesia and the Philippines, an
area also important for other marine biodiversity. For systems
like this, the outlook is grim, he added.
Northern Ireland is in a fascinating position, Dr Schoeman
explained. “The warming ocean should tend to shift species
northwards along the Irish east and west coasts, converging
on the north Antrim coast. Interestingly, temperatures are
moving up the east coast at 5 km to10 km per year, but at
only half that rate up the west coast.
“Across the land, temperatures are moving at anywhere between
2 km to 5 km per year in the east to over 20 km per year in
the west. This suggests that land-bound species tracking temperature
changes could arrive at the coast within decades.
“Typical spring temperatures around Northern Ireland are
arriving 1 to 2 days earlier each decade on the land and off
the east coast, by a half to 1 day per decade earlier along
the Antrim coast, but they are not really changing at all
along the west coast, or even arriving a few days per decade
later offshore to the northwest.
“By contrast, typical autumn temperatures are arriving 2
to 5 days later all around Northern Ireland’s coast, but are
not shifting at all on land.”
“These complicated patterns may mean little to humans - after
all, we’re talking about only a few days change per decade
- but they can be important for the seasonal timing of ecological
events, which are often quite precise.
“Despite scientific progress in so many areas, much remains
to be discovered in the sea. We cannot allow out-of-sight
to be out-of-mind. The sea provides us with many services
that society still doesn’t fully appreciate - and, without
an understanding of the changes they are likely to face, we
have little capacity to plan.”
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