• Energy Research
• 11. Sustainability close
• Oceanography close

The ocean is the primary heat sink of the global climate system. Since 1971, it has been responsible for storing more than 90% ofthe excess heat added to the Earth system by anthropogenic greenhouse-gas emissions. Adding this heat to the ocean contributes substantially to sea level rise and affects vital marine ecosystems. Considering the global ocean’s large role in ongoing climate variability and change, it is a good place to focus in order to understand what observed changes have occurred to date and, by using models, what future changes might arise under continued anthropogenic forcing of the climate system. While sparse measurement coverage leads to enhanced uncertainties with long-term historical estimates of change, modern measurements are beginning to provide the clearest picture yet of ongoing global ocean change. Observations show that the ocean is warming from the near-surface through to the abyss, a conclusion that is strengthened with each new analysis. In this assessment, we revisit observation- and model-based estimates of ocean warming from the industrial era to the present and show a consistent, full-depth pattern of change over the observed record that is likely to continue at an ever-increasing pace if effective actions to reduce greenhouse-gas emissions are not taken.

The ocean is the primary heat sink of the global climate system. Since 1971, it has been responsible for storing more than 90% ofthe excess heat added to the Earth system by anthropogenic greenhouse-gas emissions. Adding this heat to the ocean contributes substantially to sea level rise and affects vital marine ecosystems. Considering the global ocean’s large role in ongoing climate variability and change, it is a good place to focus in order to understand what observed changes have occurred to date and, by using models, what future changes might arise under continued anthropogenic forcing of the climate system. While sparse measurement coverage leads to enhanced uncertainties with long-term historical estimates of change, modern measurements are beginning to provide the clearest picture yet of ongoing global ocean change. Observations show that the ocean is warming from the near-surface through to the abyss, a conclusion that is strengthened with each new analysis. In this assessment, we revisit observation- and model-based estimates of ocean warming from the industrial era to the present and show a consistent, full-depth pattern of change over the observed record that is likely to continue at an ever-increasing pace if effective actions to reduce greenhouse-gas emissions are not taken.

Climate, energy, and food security are three of the greatest challenges society faces this century. Solutions for mitigating the effects of climate change often conflict with solutions for ensuring society’s future energy and food requirements. For example, BioEnergy with Carbon Capture and Storage (BECCS) has been proposed as an important method for achieving negative CO2 emissions later this century while simultaneously producing renewable energy on a global scale. However, BECCS has many negative environmental consequences for land, nutrient, and water use as well as biodiversity and food production. In contrast, large-scale industrial cultivation of marine microalgae can provide society with a more environmentally favorable approach for meeting the climate goals agreed to at the 2015 Paris Climate Conference, producing the liquid hydrocarbon fuels required by the global transportation sector, and supplying much of the protein necessary to feed a global population approaching 10 billion people.

Climate, energy, and food security are three of the greatest challenges society faces this century. Solutions for mitigating the effects of climate change often conflict with solutions for ensuring society’s future energy and food requirements. For example, BioEnergy with Carbon Capture and Storage (BECCS) has been proposed as an important method for achieving negative CO2 emissions later this century while simultaneously producing renewable energy on a global scale. However, BECCS has many negative environmental consequences for land, nutrient, and water use as well as biodiversity and food production. In contrast, large-scale industrial cultivation of marine microalgae can provide society with a more environmentally favorable approach for meeting the climate goals agreed to at the 2015 Paris Climate Conference, producing the liquid hydrocarbon fuels required by the global transportation sector, and supplying much of the protein necessary to feed a global population approaching 10 billion people.

As the nation clamors for new renewable energy sources, hydrokinetic technologies—including wave, current, tidal, and in-stream energy technologies—offer promising additions to the grid. Placing new technologies in ocean and tidal environments, which contain vast, sometimes sensitive resources but are, surprisingly, relatively unstudied, presents a challenge to agencies and developers alike as the industry strives to move through initial project-permitting stages in an efficient but environmentally responsible manner. “Adaptive management” approaches can allow projects to be permitted and installed while providing agencies and other stakeholders the opportunity to verify their anticipated impacts. Moreover, where actual impacts exceed expectations, an adaptive management approach allows agencies to address such impacts consistent with existing regulatory standards intended to protect marine resources.

As the nation clamors for new renewable energy sources, hydrokinetic technologies—including wave, current, tidal, and in-stream energy technologies—offer promising additions to the grid. Placing new technologies in ocean and tidal environments, which contain vast, sometimes sensitive resources but are, surprisingly, relatively unstudied, presents a challenge to agencies and developers alike as the industry strives to move through initial project-permitting stages in an efficient but environmentally responsible manner. “Adaptive management” approaches can allow projects to be permitted and installed while providing agencies and other stakeholders the opportunity to verify their anticipated impacts. Moreover, where actual impacts exceed expectations, an adaptive management approach allows agencies to address such impacts consistent with existing regulatory standards intended to protect marine resources.

Last year I traveled to Bangkok, Thailand, for the second Asia Pacific Adaptation Forum, which was called off at the last minute due to the city's worst flooding in the past 50 years. Bangkok, an urban center of great wealth in a relatively rich country, showed itself to be quite vulnerable to climate impacts. The flooding caused 815 deaths, massive displacements of population, and $45 billion in economic damage, including lasting damage to its automobile and electronics supply chains. Similarly, the landfall of Hurricane Katrina in New Orleans, Louisiana, in 2005 caused 1,836 deaths and $81 billion in damage. Thus, while it is certainly true that development can ameliorate some aspects of climate change vulnerability, we surely should not be fooled into thinking that development, sustainable or not, comprises the entire solution to the climate change adaptation challenge. At the very least, developing countries can find, and are finding, new development pathways that avoid some of the maladaptation that has already occurred in the developed world. Additionally, developing and developed countries alike can benefit from improving ecosystem management as an integral part of policies to help reduce vulnerability and increase resilience in the face of climate change.