The report says that sea surface
temperature is predicted to increase by 2ēC on average globally by
2080-2100. The consequences of this increase will include changes in
ocean circulation and higher water column stratification, where water of
different densities forms distinct layers instead of mixing, affecting
the availability of nutrients.
The depletion expected in the amount of
plankton in the marine food web could reduce fish biomass in 47% of the
total global ocean area, especially in tropical oceans.
But phytoplankton and zooplankton
reduction will affect different regions in different ways. In the North
Sea and temperate north-east Atlantic, higher stratification and lower
nutrient levels will reduce phytoplankton growth. In the Baltic, Barents
and Black Seas, it is expected to increase.
Guillem Chust, an Azti-Tecnalia researcher
and the lead author of the paper, said: “In the ocean regions that lose
more phytoplankton and zooplankton biomass, fish biomass may also
decrease dramatically.” He said this would especially affect pelagic
species − deep-sea fish that are not bottom dwellers.
He said the oceans’ role in moderating
climate change would also be damaged: “As there will be less
phytoplankton, absorption of CO2 from the atmosphere by the oceans will
be lower, as plankton is responsible for half of the planet's
photosynthetic activity. This in turn will reduce the ocean’s capacity
to regulate the climate.”
The research was undertaken as part of
Marine Ecosystem Evolution in a Changing Environment (MEECE), a European
Union project to explore the impact of climate and human activities on
One of the project's concerns is the
growing evidence of damage from ocean acidification, the process by
which emissions of carbon dioxide are making the seas increasingly acid
and hostile to some forms of marine life.
A campaign group, Global Ocean Health, has
welcomed a move by the US Environmental Protection Agency intended to
lead to the introduction of performance-based emission limits for new
power plants, which would help to reduce the threat of acidification.
“The rule would help protect productive
fisheries and oceans,” GOH says. “Although it cannot single-handedly
staunch the flow of carbon emissions that drive ocean acidification, the
rule would make a good start.”
Capping CO2 emissions per unit of power
produced would, GOH says, effectively block any new coal plants in the
US, ensuring a continued shift towards natural gas, which is cheaper
than coal. In the last six months, it says, more than 80% of the new
electricity capacity added to the US grid was renewable energy.
The campaign group also believes the rule
would dampen global investors’ appetite for coal projects by
demonstrating that the US is no longer willing to tolerate unlimited CO2
emissions from coal.
“With this policy, the world’s most
influential economic superpower would signal to global capital markets
that coal is no longer a safe investment,” GOH says.
This would add to the growing argument
that fossil fuel reserves risk becoming unusable “frozen assets” because
of their climate impact.
Source: Climate News Network