By Claire Bekker, '21
On October 8th, 2018, the Intergovernmental Panel on Climate Change (IPCC) issued a strong wake-up call to the world: we only have twelve years to avoid the most catastrophic effects of climate change . To prevent a 2ºC increase in warming from pre-industrial levels, we need to meet stringent goals for CO2 emissions. By 2030, emissions must be 45% lower than 2010 levels. By 2050, we need to reach zero net emissions (in which case we would either emit no CO2 or remove as much CO2 from the atmosphere as we released).
The global mean temperature has risen by approximately 1ºC since the pre-industrial era and we are already experiencing the effects of anthropogenic climate change: more extreme weather patterns, rising sea levels, and melting Arctic sea ice. These impacts are expected to accelerate as warming increases. IPCC scientists predict that global warming is likely to reach 1.5ºC between 2030 and 2052, but we are also well on our way to a 2ºC increase in warming if CO2 emissions continue at their current rate. Our challenge is to limit warming to 1.5ºC, because the difference between 1.5º and 2ºC is significant. If we reach 2ºC, the Arctic will have an ice-free summer every decade, 10 million more people will be exposed to rising sea levels, and ecosystems such as coral reefs will be irreversibly lost .
Climate change will threaten nearly every aspect of human society, with a disproportionate impact on developing nations and indigenous populations. If warming rises to 2ºC instead of 1.5ºC, several hundred million more people will be at risk for poverty by 2050, mortality will increase due to heat-related illness and infectious disease, and crop yields will decrease, especially in Sub-Saharan Africa, Southeast Asia, and Central and South America.
So the question remains: how will we avoid the 2ºC threshold? In addition to accelerating our current efforts (think wind and solar energy, energy efficiency, conservation), we must also find innovative ways to limit CO2 emissions and warming. Published in Frontiers in Marine Science just four days before the IPCC’s special report, one study examines the potential of ocean-based solutions to prevent global warming . Oceans, which already sequester 25% of anthropogenic CO2 emissions, play an extremely important role in climate regulation. However, ocean-based solutions have been overlooked in the past. To remedy this, Dr. Jean-Pierre Gattuso and researchers with The Ocean Solutions Initiative analyzed 13 different ocean-based measures to combat climate change. These measures could reduce atmospheric CO2 concentrations, increase the proportion of solar energy reflected back into space, protect marine ecosystems, and increase biological resilience to climate change. Gattuso et. al not only considered each measure’s effect on warming, but also feasibility issues, such as cost-effectiveness, available technology, and governance.
Ocean-based renewable energy was identified as the promising solution, both in terms of CO2 emissions and feasibility. Efforts are already underway to create wind farms and generate energy from waves, tides, marine currents, and even temperature or salinity gradients . These projects could easily be scaled up to fulfill their full potential. Local conservation is also critical; if we reduce marine pollution and conserve or restore marine habitats, coastal vegetation can increase CO2 uptake .
The larger-scale, more controversial methods raised some uncertainty, both in terms of feasibility and potential side effects on marine life. Comparable to atmospheric-based geoengineering solutions to remove CO2, these interventions would increase the ocean’s capacity to sequester CO2 from the atmosphere. Scientists could add massive quantities of alkaline material to the ocean, which would allow it to absorb more CO2 without becoming acidic. If the ocean was fertilized with iron (a key limiting nutrient for phytoplankton), photosynthetic organisms could also consume more CO2. With these geoengineering solutions, we must consider important questions of international governance, authority, and implementation. They could also have unknown consequences on existing ecosystems. As a result, Gattuso and his colleagues do not recommend these solutions yet .
While not all the measures studied in this report were feasible or even advisable, we must continue to research creative solutions. If we want to prevent future warming, we need to mobilize climate action on all fronts— on land, in the ocean, and in the atmosphere. All of these earth systems are connected— to climate and to each other— and we must find a way to integrate and amplify different solutions.
 Intergovernmental Panel on Climate Change. "Rapid response needed to limit global warming: Summary for Policymakers of IPCC Special Report on Global Warming of 1.5°C approved by governments." ScienceDaily. ScienceDaily, 8 October 2018.
 Gattuso, J.P., Magnan, A.K., Bopp, L., Cheung, W.L., Duarte, C.M., Hinkel, J., Mcleod, E., Micheli, F., Oschlies, A., Middleburg, P., Portner, H.O., Rau, G.H. Ocean Solutions to Address Climate Change and Its Effects on Marine Ecosystems. Front. Mar. Sci. 2018 Oct 04; DOI: 10.3389/fmars.2018.00337
 TerraTherma. Five Kinds of Sea-Based Renewable Energy. Available from : http://terratherma.co.uk/five-kinds-sea-based-renewable-energy/.