The Economist - USA (2019-12-21)

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The UN Intergovernmental Panel on Climate Change (IPCC)’s report

on the ocean and cryosphere, published in September 2019, finds

overwhelming evidence that global warming has reached 1°C above

pre-industrial levels and is making the ocean warmer, more acidic and

less productive. Melting glaciers and ice sheets are causing sea-level

rise, and extreme weather events are becoming more severe.

Under the Paris Agreement, 187 countries are committed to limiting

global warming to well below 2°C and pursuing efforts to achieve a

tighter limit of 1.5°C.

The report demonstrates the risks to the ocean economy if emissions

are allowed to increase. But it also highlights the opportunities from

the blue economy, in which sustainable ocean-based industries cut

carbon emissions and create resilient coastal communities.

The IPCC says that the ocean has absorbed more than 90% of the

heat in the climate system caused by manmade carbon emissions.

Ocean warming reduces levels of oxygen and nutrients in the water.

By 2100, the ocean will absorb two to four times more heat than it

has in the past 50 years, even if global warming is limited to 2°C, and

five to seven times more at higher emissions levels. The ocean has

also absorbed 20-30% of human-induced carbon dioxide since the

1980s, increasing the acidity of water.

Damage to marine life

Ocean warming and acidification are damaging and disrupting

marine life. Fish populations have declined, the report says, and

will fall further, especially in tropical areas, though there may be

increases in the Arctic. Overall, the report expects a 15% decline in

the total mass of marine animals by 2100, and a drop of up to 25%

in fish catches. Revenue potential in the fishing industry could fall by

around 10% by 2050 in most of the world’s fishing countries.

Tourism, another important sector in the ocean economy, will be

badly affected by climate change. The loss of coral reefs caused by

marine heatwaves and acidification could lead coastal tourism to

lose up to US$3bn per year, even if global warming is limited to well

below 2°C, and up to US$5.8bn annually if carbon emissions increase

further, the report warns.

Sea-level rise and extreme weather

The IPCC finds that as glaciers and ice sheets have melted, sea levels

rose by some 15cm in the 20th century, and they are now rising twice

as quickly at a rate of 3.6mm per year. Sea-level rise will increase the

frequency and strength of extreme weather events such as flooding

and storms. Once-in-a-century weather events will occur annually by

2050. Without major investment in adaptation, flood losses in large
      coastal cities could increase from US$6bn today to US$1trn by 2050,
      and some island nations are likely to become uninhabitable.

“The world’s ocean and cryosphere have been ‘taking the heat’

from climate change for decades, and consequences for nature and

humanity are sweeping and severe,” says Ko Barrett, vice-chair of

the IPCC. “The rapid changes to the ocean and the frozen parts of

our planet are forcing people from coastal cities to remote Arctic

communities to fundamentally alter their ways of life,” she adds. “By

understanding the causes of these changes and the resulting impacts,

and by evaluating options that are available, we can strengthen our

ability to adapt.”

Climate-change risks and opportunities for the blue economy

The blue economy is on the frontline of threats from climate change. But it also offers

solutions to cut carbon emissions and create sustainable businesses and communities

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The IPCC report highlights how the blue economy can help mitigate

carbon emissions and adapt to climate change, creating many

social and economic benefits. For instance, restoration of vegetated

coastal ecosystems such as mangroves, tidal marshes and seagrass

meadows could absorb and store around 0.5% of annual global

carbon emissions. These ecosystems also provide greater storm

protection to coastal communities and improve water quality

and fish stocks. Public-private partnerships are needed to finance

large-scale ecosystem restoration projects.

New opportunities

The blue economy is creating new opportunities for shipping

companies to develop zero-carbon fuels and propulsion technologies

to cut shipping’s carbon emissions by 50% by 2050. The IPCC also

identifies opportunities for offshore renewable-energy technologies

such as wind, tidal, wave, algal biofuels, and thermal and salinity

gradient to mitigate carbon emissions.

Further analysis of the benefits of the blue economy is provided by

the High Level Panel for a Sustainable Ocean Economy, a group of

14 world leaders, including those from Japan, Norway and Canada.

The panel analysed ocean solutions including offshore renewables,

shipping, ecosystem restoration, fisheries and aquaculture, and

seabed carbon storage. It says that countries could do more to include

such solutions in their plans towards achieving the Paris Agreement.

Ocean solutions could save nearly 4bn tonnes of carbon by 2030, and

more than 11bn tonnes by 2050—equivalent to the emissions from

the world’s coal-fired power stations. They could contribute up to 21%

of the reductions needed to close the gap between current emission

levels andwheretheworldneedstobetolimitglobalwarmingto 1.5°C.

ProfessorOveHoegh-Guldberg,directoroftheGlobalChange

Institute at the University of Queensland and lead author of the High

Level Panel’s report says: “This analysis offers new hope in the fight

against climate change. Most options are ready to be implemented

today and could offer many co-benefits in terms of creating jobs,

improving air quality and human health, and supporting livelihoods.

Bold political leadership and clear policy signals will be required to

capitalise on the full potential of the solutions, coupled with strong

national institutions and international cooperation to ensure their

effective implementation.”

21%

Maximum

annual

emissions

reductions

(GtCO

e)* 2

Ocean-based

renewableenergy

Ocean-based

transport

Coastaland

marineecosystems

Fisheries,aquaculture

and dietaryshifts

Carbonstorage

in seabed

Totalocean-based

solutions

Needed

annual GHG

emissions

reductions

by 2050

(56 GtCO 2 e)

0

4

8

12

5.4

1.8

1.4

1.2

2.0

11.8

Contributionof five ocean-basedclimatesolutions

to mitigating climate change by 2050

Source: High Level Panel for a Sustainable Ocean Economy