Through the ocean darkly
Carol Anne Clayson, Director of the Ocean and Climate Change Institute at the Woods Hole Oceanographic Institution details the impact the oceans have on climate systems…
In the final draft agreement adopted by the 21st Conference of the Parties in Paris last year, the ocean is mentioned only once – and that is only in passing and only in the preamble. This is understandable in light of the fact that the ocean works largely unseen to regulate and maintain Earth’s climate. But we ignore the ocean’s importance to climate and human society at our peril. As we move forward with the crucial goal of keeping human-caused warming to below 1.5ºC and ensuring that developing countries are able to meet the challenges of a changing climate, we must also pay attention to understanding how human activity is affecting, and will continue to affect, our planetary life-support system.
Climate change has been described as one of the greatest challenges of our time. When one considers the possible effects brought on by increased warming, including drought, flood, famine, and mass migration, that is almost certainly the case. Predicting the timing, location, and impacts of changes that have their root in human action, as well as those caused by natural variability, is central to our ability to develop effective solutions that anticipate immediate and future needs. Any serious effort to address climate change and mitigation must include investment in more ocean research.
The ocean drives our climate system in many ways. It covers more than two-thirds of Earth’s surface and holds the majority of water that eventually falls on land as rain or snow. The ocean drives air and water circulation patterns that heavily influence global and regional weather patterns and climate.
The ocean is storing roughly 90% of the increased heat added to our climate system. Measurements of this stored heat, while incomplete, show the trend clearly because it is so much larger than the uncertainties in the observations. To put it bluntly, global warming is ocean warming. This is especially troubling because even if we were to curtail human-caused greenhouse gas emissions overnight, heat stored in the ocean would affect global atmospheric temperatures for decades or centuries to come, since the ocean retains this heat much longer than the atmosphere.
The ocean also stores about half of the man-made carbon dioxide (CO2) emitted from 1800 to 1994. However the ability of the ocean to buffer CO2 appears to be decreasing over time for reasons still not well understood. In the meantime, the steady increase in dissolved CO2 is already causing harm to marine life by decreasing the seawater pH and hampering the ability of some organisms to grow shells or skeletons. The loss of highly productive ecosystems that rely on coral reefs and tiny zooplankton will have widespread impacts throughout the ocean and on land. The complexity of the problem combined with our lack of data means that we are, in effect, walking blindly into a dark room that is our future.
Although ocean science has advanced in recent decades to the point where we can identify areas of concern such as these, key pieces of our understanding of the global climate system and the ocean in particular are still missing. Our knowledge of the deeper ocean is limited because of significant gaps in the data. We have almost no consistent, long-term data from deeper than 1 mile down – in a global ocean that is, on average, more than 2 miles deep.
The processes that drive the transfer of heat, carbon, and water between the ocean and the atmosphere and between the upper and lower regions of the ocean are even more poorly understood, again due to a lack of observations. We also lack the information necessary to assess how much more heat and CO2 the ocean can absorb, and even how much of the current variability is naturally occurring or human-induced. Understanding and predicting these exchanges is vital to predicting how much, how fast, and where temperature, sea level, ocean pH, and other key aspects of our climate system will change over the long-term.
Addressing these gaps will require greater investment in ocean research. Current funding levels are woefully insufficient to begin filling the gaps or to sustain the number of researchers needed to collect and analyse the data and to update the models to prepare us for the future. Even when data is available, opportunities to take advantage of it are being missed. For example, United Nations Framework Convention on Climate Change (UNFCCC) accounting mechanisms do not currently include information about how and where the ocean is transporting and storing carbon.
The key to understanding our future lies in understanding the ocean. Without an increased level of funding for ocean research and an effort towards a global ocean observing system similar to our investments in atmospheric measurements, our current scientific efforts to advance our prediction of global climate change will not yield the hoped-for results that negotiators so optimistically announced just a few months ago.
Carol Anne Clayson is the director of the Ocean and Climate Change Institute at Woods Hole Oceanographic Institution and a senior scientist in the physical oceanography department.
The Woods Hole Oceanographic Institution is a private, non-profit organization on Cape Cod, Mass., dedicated to marine research, engineering, and higher education. Established in 1930 on a recommendation from the National Academy of Sciences, its primary mission is to understand the ocean and its interaction with the Earth as a whole, and to communicate a basic understanding of the ocean’s role in the changing global environment.
Carol Anne Clayson
Ocean and Climate Change Institute – Woods Hole