PARIS: Humanity
must heal oceans made sick by climate change and pollution to protect marine
life and to save itself, experts warned days before the release of a major UN
report. By absorbing a quarter of manmade CO2 and soaking up more than 90
percent of the heat generated by greenhouse gases, oceans keep the population
alive - but at a terrible cost, according to a draft of the Intergovernmental
Panel for Climate Change (IPCC) assessment seen by AFP.

Seas have grown
acidic, potentially undermining their capacity to draw down CO2. Warmer surface
water has expanded the force and range of deadly tropical storms. Marine
heatwaves are wiping out coral reefs, and accelerating the melt-off of glaciers
and ice sheets driving sea level rise.

"The last
book of the Bible talks about the four horseman of the Apocalypse," said
Dan Laffoley, strategic lead for ocean protection at the International Union
for the Conservation of Nature. "For the oceans, the lead horseman is
surface warming," he told AFP. "The three others are ocean heating,
loss of oxygen and acidification." There are at least three types of
actions humans can take to help repair the damage and ensure that oceans don't turn
from friend to foe, scientists say.

Restoration,
Protection

Less than seven
percent of oceans - which cover 70 percent of Earth's surface - benefit from
some form of regional or national protection, often with minimal enforcement.
Ocean advocates and experts say the area safeguarded must be vastly expanded.
"We need to protect 30 percent of the ocean by 2030," said Lisa
Speer, director of the international oceans program at the National Resources
Defense Council in Washington DC. "This cannot be achieved without a high
seas agreement," she added. UN negotiations for a treaty to regulate
exploitation of the high seas - waters beyond national jurisdiction covering
nearly half the planet - began last fall, and could take years to complete.

At the same time,
regions not included in marine parks or conservation areas "must be
managed in a cautious and durable way," Tom Dillon, Vice President of Pew
Charitable Trust said. Restoring coastal mangroves and seagrass meadows,
meanwhile, would draw down CO2 emissions, and shield coastal communities from
storm surges as a bonus. These "blue carbon" ecosystems could
potentially stock just under a billion tons of CO2 per year, about two percent
of current emissions, according to the UN report.

Renewable energy

Off-shore and
ocean-based renewable energy - including wind, wave, tidal, currents and solar
- could meet a significant slice of future energy demand, numerous studies have
shown. Such schemes are mostly experimental and thus costly per unit of energy
generated, but economies-of-scale are possible. Floating wind farms, for
example, fuelled by high wind speed over the open ocean could eventually
generate more electricity than those on land, Carnegie Institution for Science
researchers reported in PNAS.

In winter, North
Atlantic wind farms "could provide sufficient energy to meet all of
civilization's current needs," the authors said. "That's a bit of
fantasy, but it makes the point that these technologies have not been
sufficiently developed," said Jean-Pierre Gattuso, a senior scientist at
France's National Centre for Scientific Research. There are several ready to be
scaled up, he said.

Geoengineering

The failure of
humanity to draw down planet-warming greenhouse gases - which continue to rise
year-on-year - has opened the door to other ideas once thought risky or
far-fetched, such as injecting particles into the upper atmosphere to deflect
the Sun's radiation.  Some geoengineering
schemes to cool Earth's surface or reduce CO2 are ocean-based. One that has been
tested with inconclusive results involves sowing the open ocean with iron to
create phytoplankton colonies that absorb CO2 as they photosynthesise. When the
tiny creatures die, they drag the CO2 into the inky depths.

Another scheme
would brighten mirror-like marine clouds to reflect sunlight back into space.
Spreading long-lasting white foam across vast expanses of open water would - in
theory - have the same effect. Scientists from Princeton and Beijing Normal
University recently costed a plan to build an underwater barrier in front of an
Antarctic glacier the size of England to help prevent warm ocean water from
eroding its underbelly, thus preventing the glacier from slipping into the sea.
The price tag was several hundred billion dollars. - AFP