Scientists at the Stockholm Environment Institute (SEI) have released a new study that has placed the effects of climate change on the world’s ocean ecosystems under the spotlight. They predict climate change alone could reduce the economic value of key ocean services by up to US$2trn a year by 2100.
The scientists are now calling for a global, integrated approach to protect oceans from converging threats.
An executive summary of the report, Valuing the Ocean, has been released today, as the scientists behind the study are hoping to urge world leaders to make the oceans a priority in global sustainability goals, especially before the Rio+20 Earth Summit in June.
The study is the work of an international, multi-disciplinary team of experts, including SEI researchers. Their aim was to quantify the costs of ocean degradation, which the scientists said is often invisible in the cost-benefit analyses that guide policy.
The analysis calculates the cost over the next 50 and 100 years respectively in terms of five categories of lost ocean value:
- Sea-level rise
- The ocean carbon sink.
The scientists evaluated the five categories under high- and low-emissions scenarios.
So what were the main findings? According to the report, by 2100, the annual cost of the damages from "business as usual" emissions, projected to lead to an average temperature rise of 4°C, is estimated to be US$1.98trn, which is equivalent to 0.37pc of future global GDP.
The scientists said a rapid emission reduction pathway that limited temperatures increases to 2.2°C would avoid almost US$1.4trn of those damages.
"These figures are just part of the story, but they provide an indication of the price of the avoidable portion of future environmental damage on the ocean – in effect the distance between our hopes and our fears," said Frank Ackerman, director of the Climate Economics Group at SEI-US.
He said the cost of inaction increases greatly with time, a factor that climate change accounting must factor in.
The Valuing the Ocean report also looked at the convergence of multiple stressors such as acidification, ocean warming, hypoxia, sea-level rise, pollution, and overuse of marine resources. It said such stressors could lead to damages far greater than just from individual threats.
The scientists also pointed to how the study does not put a monetary value on the total projected damages, many of which involve immeasurable losses, such as the eradication of species.
"We must develop an integrated view of how our actions impact the ocean, and threaten the vital services it provides, from food to tourism to storm protection," said Kevin Noone, director of the Swedish Secretariat for Environmental Earth System Sciences at the Royal Swedish Academy of Sciences, and co-editor of the report.
"The global ocean is a major contributor to national economies, and a key player in the earth’s unfolding story of global environmental change, yet is chronically neglected in existing economic and climate change strategies at national and global levels," said Noone.
Co-author of the report Julie Hall is based at the New Zealand National Institute of Water and Atmospheric Research.
"We urgently need to devise a management system that works across scales from local to global, and allows us to optimise our use of marine resources in a sustainable way, given simultaneous, and often synergistic, threats," said Hall today.
As well as seeking action from global leaders on oceans and climate change, the authors of the report have also called for more local measures, such as marine protected areas to boost the resilience of marine ecosystems. This would protect such ecosystems against the risk of extreme events like mass coral bleaching and more intense tropical storms, claimed the scientists.