Carbon Sequestration at Sea

Because carbon dioxide (CO2) is one of the major greenhouse gases causing the gradual warming of the Earth's surface and potentially disastrous changes to global climate, CO2 ocean sequestration is being explored as one possible approach to limit the accumulation of greenhouse gases in the atmosphere. CO2 released in very cold deep-water forms ice-like solids known as hydrates. There are a number of experiments ongoing to inject carbon dioxide into the deep ocean, and to then gather data in the vicinity of the CO2 injection point to improve our understanding of the basic physical phenomena, and to apply this data to refine the accuracy of predictive computer models that are needed to evaluate environmental impacts. Model
validation is a first and necessary step to assess the physical, chemical and environmental effects of CO2 sequestration in the deep ocean.

CO2 ocean sequestration is a concept that was conceived in the early 1980s to avoid the rapid build-up of carbon dioxide in the atmosphere. However, there is rather daunting amount of scientific uncertainty surrounding impacts on the marine environment. Full-scale sequestration requires a lot more research before this concept sees the light of day. Using relatively shallow oceans (at roughly 800 meters) as a massive sink for removing immense amounts of CO2 pollution from global industry is merely transferring contaminants from land to sea. And anything stored that deep will be very difficult to recover and may well leak. Moving the problem of CO2 pollution encourages the continued use of fossil fuel for power generation. It would be much better to address climate change through clean energy solutions like hydrogen fuel cells, avoiding CO2 production in the first place.

In addition to increasing hydrates, the injection of CO2 results in lower pH (more acidic) waters. Creatures living on the sea floor (benthic communities) near the injection point could be affected by the acidic water; more mobile (swimming) animals are not expected to be harmed. An increase in atmospheric CO2 transfer into shallow waters has also been identified as an inhibitor in coral calcification, the building material for coral reefs.

Mitigation: Slowing the Rate of Climate Change

There is still some hope that we have the capacity to avoid accelerating climate change or at least, to slow the rate of change and improve our odds of addressing its impact. However, this issue lies at the intersection of social/political and biological/physical systems. An overwhelming majority of scientists think that continued growth of greenhouse gas emissions will certainly raise average global temperatures and change regional climates; the only questions are how much and how fast this will occur under various scenarios. The uncertainties associated with each modeling scenario have become an obstacle to adoption of a regulatory structure and related policies to reduce greenhouse gas emissions, even though the scientists have clearly called for human action to reduce greenhouse gas pollution as an imperative. While there is a lack of absolutes in scientific advice, the scientists have achieved a widespread consensus on the overall expected effect.

We are operating with a lack of political will to reverse perverse subsidies, together with
unsustainable assumptions and trends built into our economic structure, such as ever-expanding consumption. There are in fact several good processes currently underway to deal with perverse fisheries subsidies, including at UNEP, FAO and WTO. However, these efforts tend toward the lowest common denominator; they will also have to run a gauntlet of domestic implementation legislation before they become a reality. There is an almost complete lack of long-range planning, certainly a significant lack of ecosystem planning, and very little precaution built into our human development model. The precautionary approach and ecosystem management are the two pillars of sustainable management of marine resources, as embodied in international law that
must be followed. Among other consequences, we may risk political instability through failure to address climate change induced degradation of our ecosystem supports for human health and economic well-being.

Mitigation technologies have been proposed that include: nuclear power, fuel switching (using fuels with lower carbon content, such as replacing oil or coal with natural gas), reforestation, renewable energies, energy conservation and improved energy efficiency. In addition, to address shocks to our system such as human health impacts, we will need to focus on the maintenance and improvement of our public health care systems and their responsiveness to changing climate conditions and to identifying vulnerable populations.

Adaptation

Our policymakers need to find the right incentive structures to get everyone to move in the right direction. There are two choices: change our lives through the exercise of restraint, or change in response to environmental catastrophe. Human capacity to exercise restraint is a source of hope, whether the restraint comes from new knowledge or gut-level compassion. Most of us do not live anywhere near the poverty level, we have room to reduce our consumption without undercutting our quality of life – "all but the poorest of us could choose to lead materially simpler lives, and thereby do less harm and reap more joy."48 But this is a hard sell to the general public unless such "joy" is truly and clearly attainable—and feels as much like independent choice as current lifestyles.

The fundamental climate change adaptation message is about coping with constant change in comparison to what we have come to expect. The past 10,000 years, during which modern civilization arose, has been a period of climate stability relative to what we know of earth's history. However, that stability, and the predictability for food production, travel, and where and how we build things, may be put into question when we ask what the oscillations from our perturbation of the climate system will look like.

More coastal areas will need to build structures to withstand stronger storms. We will have to retreat from the beach, giving the ocean the room it needs to expand. In 1998, NOAA summarized the coastal responses as follows:

(1) Accommodate. Vulnerable areas continue to be occupied, accepting the greater degree of effects, e.g., flooding, saltwater intrusion, and erosion; advanced coastal management used to avoid the worst impacts; improved early warning of catastrophic events; and building codes modified to strengthen structures.

(2) Protect. Vulnerable areas, particularly population centers, high-value economic activities, and critical natural resources, are defended by sea walls, bulkheads, saltwater intrusion barriers; other infrastructure investments are made; and "soft" structural options such as periodic beach re-nourishment, landfill, dune maintenance or restoration, and wetlands creation are carried out.

(3) Retreat. Existing structures and infrastructure in vulnerable areas are abandoned, inhabitants are resettled, government subsidies are withdrawn, and new development is required to be set back specific distances from the shore, as appropriate.

In its latest edition, of Basins and Coasts, USAID’s newsletter on integrated management of coastal and freshwater systems, editor James Tobey has assembled a series of articles on climate change vulnerability and adaptation for coastal residents around the world²¹.  The mainstreaming of climate and the oceans has begun.

²¹ Available at http://www.imcafs.org