A new study coordinated by the Stockholm Environment Institute shows climate change alone could reduce the economic value of key ocean services by up to $2 trillion a year by 2100.

The study, Valuing the Ocean, is the work of an international, multi-disciplinary team of experts, including SEI researchers. The full report is due to be published as a peer-reviewed book later this year; a preliminary Executive Summary is being released to inform preparations for the Rio+20 Earth Summit in June.

A key part of the study is a groundbreaking analysis on ocean economics, designed to quantify the costs of ocean degradation, which are 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 (fisheries, tourism, sea-level rise, storms, and the ocean carbon sink) under high- and low-emissions scenarios.

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 1.98 trillion USD, equivalent to 0.37 per cent of future global GDP. A rapid emission reduction pathway that limited temperatures increases to 2.2°C would ‘save’ (i.e. avoid) almost $1.4 trillion of those damages.

Frank Ackerman, director of the Climate Economics Group at SEI-US, commented:

“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. The cost of inaction increases greatly with time, a factor which must be fully recognised in climate change accounting.”

A key point made in the report is that the convergence of multiple stressors – acidification, ocean warming, hypoxia, sea-level rise, pollution, and overuse of marine resources – could lead to damages far greater than just from individual threats.

The study does not put a monetary value on the total projected damages, many of which involve “priceless” losses such as the eradication of species, but it argues that given how much is already known about the potential costs, world leaders should take a precautionary approach and take strong action to protect oceans, even in the absence of complete economic data.

“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,” says 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.”