Climate 411

Why EDF is exploring marine carbon dioxide removal


The oceans are a massive carbon sink. Researchers, companies and governments are exploring whether we can engineer coastal and ocean systems to store even more carbon. But while the ocean presents us with great possibilities, it’s also a complex system where human interventions can impact everything from the ecological (species’ interactions or the habitats they depend on) to the socio-economic (food systems or economic livelihoods).  

EDF has a track record of coordinating collaborative research on natural carbon storage systems in the ocean to understand both their role in carbon sequestration and their potential to generate ecological and socio-economic benefits, as well as any associated risks.  

We’re now taking a similarly holistic approach to exploring the potential of technical approaches to marine carbon dioxide removal (or, mCDR). Our aim: to identify the areas with the greatest potential to accelerate innovation with minimal risks to people and nature.  

mCDR: different methods to increase carbon sinks 

Marine CDR is a manmade intervention in the marine environment that changes the biology, chemistry or physics of the surface ocean resulting in the net removal of carbon dioxide from the atmosphere. A few ideas have been suggested based on existing knowledge of ocean science. For example:  

  • Using fertilizers like iron sprinkled in the water in large quantities could encourage the growth of phytoplankton, microscopic marine plants, that, by sinking or being consumed, could facilitate the movement of carbon to the deep sea.  
  • Releasing minerals into surface waters that amplifies the slow natural weathering of rocks like limestone or basalt could help boost ocean’s alkalinity and increase carbon sequestration rates in the ocean.  
  • Pumping surface water to deeper depths could take carbon dioxide the ocean has absorbed from the atmosphere and mimic the natural process of phytoplankton sinking when they die.  

While these innovations seem promising, changing natural processes can result in a host of hard-to-determine impacts. For example, scientists don’t yet know whether artificial fertilization and growth could result in carbon export to the deep ocean. Therefore, we need to be cautious and examine not only the efficacy of carbon removal, but also impacts on marine life and human health. There are also complex ethical considerations associated with undertaking many of these approaches, from economic costs to impacts on livelihoods and food security across both short and long timescales. It’s critical to understand the risks as well as who will benefit, and who will bear the costs as decisions to continue research or deployment are being made.   

Why it’s time to examine mCDR’s efficacy and impacts 

It’s clear that holding warming below 2 degrees Celsius through emissions reductions and the energy transition alone will be difficult. We see a potential role for mCDR in contributing to stabilizing the climate and reaching net zero goals in the long term, which requires gaining a better understanding of benefits and risks in the short term. More and more organizations are working on mCDR, in large part driven by significant interest in the voluntary carbon market. And while funding is currently focused on evaluating the efficacy of carbon removal, we lack a solid scientific basis upon which to make reasonable decisions.  

A strong scientific foundation is critical to speeding and scaling CDR solutions. But speeding and scaling down the wrong path can ultimately reduce confidence in entire solution pathways, as well as lead to environmental harms. EDF wants to help to establish, guardrails, governance and policies to help develop a responsible research program that would allow thoughtful consideration of the full scope of both climate and ecological and socio-economic implications of mCDR development.   

EDF applies a systems perspective in examining climate solutions, with mCDR fitting within our existing and complementary efforts related to natural climate solutions, emissions reductions, carbon markets and solar geoengineering methods. We also have a long track record of working with academe, industry, governments, other NGOs, community groups and other civil society organizations to provide society with the understandings required to make science-based decisions.   

While EDF is not supporting widespread deployment of mCDR methods at this time, we are engaging in the following ways: 

  • Assessing research needs, contributing to research, advocating for research code of conduct, and supporting the development of rigorous standards for assessing the safety of any research in this space.  
  • Examining permitting and regulatory needs to help inform recommendations and policies.  
  • Developing effective engagement strategies with communities and interested parties around mCDR research. 
  • Creating a holistic framework to evaluate different benefits, risks and tradeoffs of different types of mCDR.  
  • Advocating for the developing of a robust federal research initiative on marine CDR 

Emissions reduction remains EDF’s number one priority and primary focus. However, as we work to address near term warming and with it limit some of the most worrisome impacts of climate change that we’re already experiencing, we need to research new technologies that show promise. Instead of jumping into mCDR with a Gold Rush mentality, it’s critical to develop an evaluative framework for looking at the impacts of these new technologies across the multiple dimensions that affect the environment and people’s wellbeing and engage civil society in the process. 

Also posted in Geoengineering, News, Science / Authors: , / Comments are closed

Resolving scientific uncertainties in nature-based climate solutions: Location, location, location

Drone shot of mangrove trees off the coast of the Yucatán Peninsula in Mexico.

Drone shot of mangrove trees off the coast of the Yucatán Peninsula in Mexico. Carlos Aguilera / EDF Mexico

The world needs nature-based climate solutions (NbCS). These approaches use conservation, restoration, and management of natural and agricultural systems to retain existing, and sequester additional, carbon while reducing emissions of CO2 and other greenhouse gases. NbCS have been suggested to meet 20-30% of the world’s climate goals. Correspondingly, nature-based actions are included in the national commitments of 63% (104 of 168) of the signatories of the Paris Agreement.

However, defining the climate impact of different solutions requires accurate scientific measurement and accounting of greenhouse gas mitigation, including how long that benefit lasts. Where we lack accurate measurements and estimates of future durability, we cannot yet rely on NbCS to meet our climate goals.

Assessment of the science on NbCS
Environmental Defense Fund recently worked with experts in academia and other conservation and research institutions to assess the scientific confidence in more than 40 NbCS that have been proposed. The results of that inquiry are both optimistic and sobering.

The four most frequently credited NbCS by the four major carbon credit registries have high scientific confidence – tropical and temperate forest avoided conversion or degradation and reforestation. The confidence of the scientific community in those NbCS supports investing in these as climate solutions and demonstrates that we can develop sufficient understanding of process, measurement, and accounting methods necessary to meet high quality crediting requirements.

However, the experts concluded that 90% (39/42) of the proposed NbCS assessed in the study currently have insufficient scientific evidence for having climate impact we can count on. Within that 90% are NbCS like avoided conversion and degradation of systems as different as mangroves and boreal forests (see below for why).

Promisingly, the experts do have confidence that we can remedy this situation: focused research over the next five years could resolve many of the remaining questions for two-thirds of those pathways. Given that some, like agroforestry, tropical peatland conservation, and biochar additions are also estimated to have large-scale climate impacts, this study provides a roadmap for prioritizing research efforts.

The importance of location
Every NbCS is different, and so are the specific uncertainties and research needs. Prediction of how natural systems may change as the climate changes – affecting their carbon storage and greenhouse gas emissions – is inherently uncertain. We are better at modeling some systems (like tropical forests) than others (like seagrass beds). But all NbCS pathways have something in common – location matters.

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Also posted in Basic Science of Global Warming, Carbon Markets, Forest protection, Greenhouse Gas Emissions, News, Plants & Animals, Science / Comments are closed

Why melting polar ice is a debt we can’t afford to carry

Near Palmer Station, Antarctica. Photo: Alice Alpert

We now know it’s official – 2023 was the warmest year ever recorded.

Citizens across the globe felt the impacts long before it was confirmed. There were unprecedented wildfires in Canada that turned the New York sky orange. Phoenix saw a record-breaking 31 consecutive days with temperatures topping 110 degrees.

Along with these very immediate impacts, we also need to pay attention to the longer-term impacts of climate change. Specifically, when it gets hotter, ice locked in glaciers and ice sheets melts and ends up as water in the ocean. It takes a long time to melt, but eventually all that water raises the level of the ocean.

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Also posted in Arctic & Antarctic, Basic Science of Global Warming, Extreme Weather, Science / Read 7 Responses

The science is clear – climate change is causing more damaging hurricanes in Florida

Flooding in Tampa from Hurricane Idalia. Photo: Andrew Heneen, CC BY 4.0, via Wikimedia Commons

(This post was co-authored by EDF Senior Climate Scientist Ilissa Ocko)

Hurricanes are complicated, and their characteristics depend on a number of factors, which makes it difficult to tease out certain trends and predict the future. But what is scientifically clear is that human-caused climate change is a key reason that hurricanes are more destructive – especially in Florida.

Hurricanes are becoming stronger faster. They are less predictable and thus more dangerous because there is less time to prepare and evacuate. Flooding from hurricanes is worsening due to higher sea level, more rainfall, and slower storm speeds. 

Florida has always been more vulnerable to hurricanes and tropical storms than any other U.S. state because its exposed, southern location is surrounded by warm waters. There are almost twice as many hurricanes that hit Florida as Texas, the second most impacted state. But shifting atmosphere and ocean conditions from climate change – caused by heat-trapping gases emitted from human activities – are making hurricane season even worse for Floridians. Here’s how:

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Also posted in Basic Science of Global Warming, Extreme Weather, Greenhouse Gas Emissions, News, Science / Authors: / Comments are closed

Bonn climate talks: The Global Stocktake, oceans, food and nature are issues to watch

EDF’s delegation to the climate talks taking place in Bonn, Germany from June 5 to June 15 give us some insights into the issues they’re following. 

Flags on clear sky. Getty.

Next week, climate negotiators will convene in Bonn, Germany for a two-week negotiation session that will serve as an important marker on the road to the COP28 climate talks in Dubai this November. The outcome of the talks, known as SB58, will set the stage for the negotiations at COP28, giving us an indication of what needs to happen in the months leading up to those pivotal talks.

Every year the climate negotiations become more urgent as we draw closer to the timelines for meeting the Paris Agreement goals. The task is even more challenging when considering the other crises the world faces, like economic disruption, energy insecurity and food scarcity. We need effective solutions that can solve for these multiple challenges simultaneously. The talks in Bonn are an important opportunity to gauge progress and push forward key action points that address these various challenges, in the lead up to COP28, and beyond.

EDF’s delegation to the Bonn climate talks are closely monitoring various important issues inside and around the negotiations. These include the Global Stocktake process, food, fisheries and ocean issues, and efforts to expand high-integrity carbon market cooperation.

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Also posted in Agriculture, Carbon Markets, Forest protection, International, News, Paris Agreement, United Nations / Comments are closed

What you need to know about hurricanes and climate change

Photo: NOAA

This post was co-authored by EDF Postdoctoral Climate Science Fellow Tianyi Sun

Today Hurricane Laura made landfall in Louisiana as a Category 4 hurricane, causing death and destruction. Louisianans and Texans in its path are now mourning and looking ahead to a long and painful recovery.

Laura had winds up to 150 miles per hour, making it one of the strongest hurricanes on record to ever hit the Gulf Coast in the United States. It tied the record for how quickly it intensified, driving questions about the role of climate change in creating and fueling this monster storm.

A look at the latest science

Scientists have been actively studying how climate change affects hurricanes for decades, and the evidence that it can influence several aspects of hurricanes continues to grow.

Overall, climate change is making these already dangerous weather events even more perilous. They are stronger, wetter, slower, and intensify more rapidly. Major storms are occurring more often and piling on heavier rainfall, and scientists anticipate the strongest storms will continue to increase in frequency. Sea level rise, along with stronger winds, are also worsening storm surges, causing more coastal flooding.

All aspects of hurricanes – from formation to track to strength to damages – can be influenced to some degree by climate change, through warmer waters, more moisture in the atmosphere, changing air patterns, and sea level rise.

For some connections, such as how climate change affects hurricane strength and its damages, the science is simple and robust. For other connections, such as how climate change affects hurricane formation and track, the science is more complicated and nuanced.

Here we break down what we know about how climate change affects four key aspects of hurricanes


1. Hurricane formation – competing factors at play
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Also posted in Basic Science of Global Warming, Extreme Weather, News, Science / Comments are closed