Replay–A Carbon Offsets Primer, The Blue Carbon Initiative, What Are Blue Carbon Ecosystems? and the Comeback of Seagrass Meadows

by | Aug 2, 2021 | Podcasts, The Climate Daily

A carbon offsets primer, plus the Blue Carbon Initiative. What are blue carbon ecosystems? And the comeback of seagrass meadows.



Seagrass is a flowering marine plant whose blades form dense meadows in shallow, sheltered areas along coastlines. 

Did you know Seagrass evolved over 70 million years ago from terrestrial grass? and is one of the most diverse and valuable marine ecosystems on the planet? That it plays a crucial role in combatting climate change, ensuring food security, protecting coastlines, enriching biodiversity, controlling disease and filtering water?

Uh no. Then what do you know. I know I’m glad you’re on my team.

Okay, so you didn’t know seagrass can capture carbon from the atmosphere up to 35 times faster than tropical rainforests? Seagrass is found in the coastal regions of 159 countries on six continents and covers an area of almost 116,000 square miles. That’s an area bigger than the state of Arizona. They are also home to fisheries that not only provide food and livelihoods to coastal residents but help increase ocean biodiversity.

Why does this matter to us? Seagrass meadows cover only 0.1 per cent of the ocean floor but store around 18 per cent of oceanic carbon.

That’s why the loss of underwater seagrass meadowlands and associated losses in the ecosystem developed in these seagrass meadowlands in terms of goods and services, can have major ecological, socioeconomic, and political ramifications. The recent estimated recent loss of 36% of seagrass meadows in Western Australia’s Shark Bay from extreme temperature events resulted in declines of herbivorous species like green turtles and dugongs, seagrass-associated fish populations, even the closure of scallop and blue swimmer crab fisheries.

The good news is From the Gazi Bay, in Kenya, to Maputo Bay, in Mozambique, all the way to Dale Bay in Wales, projects to restore seagrass are gathering pace, thanks to initiatives by the GEF , ACES and the Blue Carbon Initiative, seagrass meadows are coming back. 

DEEPER DIVE: UNEP/Seagrass, Out of the Blue, ACES, Seagrass World Atlas



Jeffrey just mentioned blue carbon initiative and letter combinations like GEF and ACES. And if you’re like me, you probably just asked yourself, “What the heck is blue carbon, and why does it matter to me?”

According to Wikipedia, blue carbon refers to carbon dioxide removed from the atmosphere by the world’s ocean ecosystems, mostly algae, mangroves, salt marshes, seagrasses and macroalgae, through plant growth and the accumulation and burial of organic matter in the soil. 

Sea grasses, mangroves, and salt marshes along our coast “capture and hold” carbon, acting as something called a carbon sink. These coastal systems, though much smaller in size than the planet’s forests, sequester this carbon at a much faster rate, and can continue to do so for millions of years.  Most of the carbon taken up by these ecosystems is stored below ground where we can’t see it, but it is still there. The carbon found in coastal soil is often thousands of years old!

That’s why the continued existence of blue carbon ecosystems matters to us. Their restoration is a natural way for humans to stave off atmospheric accumulation of CO2, which could keep us below 1.5 C, while we figure out how to go completely net-zero by 2050.

DEEPER DIVE: UNEP/Seagrass, Out of the Blue, ACES, Wikipedia, NOAA




Speaking of Blue Carbon, did you know 83% of the global carbon cycle circulates through the world’s oceans? Or that Blue Carbon ecosystem habitats cover less than 2% of the planet’s coastal area, yet they sequester 50% of all ocean sediment carbon?

When degraded or destroyed, these ecosystems emit the carbon they’ve stored for centuries into the atmosphere and oceans and become sources of greenhouse gases. Experts estimate that as much as 1.02 billion tons of carbon dioxide are being released annually from degraded coastal ecosystems, equivalent to 19% of emissions from tropical deforestation globally.

That’s why the International Blue Carbon Initiative matters to us. It’s a coordinated, global program focused on mitigating climate change through the conservation and restoration of coastal and marine ecosystems. The BCI coordinates with the International Blue Carbon Scientific Working Group and International Blue Carbon Policy Working Group. These groups provide guidance for needed research, project implementation and policy priorities. Projects BCI and these groups have collaborate on include:

  1. demonstrate the climate mitigation potential and viability of blue carbon projects to international policy, national governments and local managers,
  2. develop science-based methodologies that can be used worldwide, and
  3. build capacity with indigenous communities to protect and manage coastal ecosystems in blue carbon rich-countries.

DEEPER DIVE: UNEP/Seagrass, Out of the Blue, ACES, Wikipedia, NOAA, Blue Carbon Initiative, Blue Carbon Projects



Let’s talk carbon offsets.  Carbon offsets are a form of trade. THey are purchased to fund projects that reduce your GHG footprint and vary from forest restoration to power plants and factory upgrades, or building energy efficiency renovations. 

Offsets are measured in tonnes of carbon dioxide-equivalent (CO2e). One tonne of carbon offset represents the reduction of one tonne of carbon dioxide or its equivalent in other greenhouse gases.

How much do carbon offsets cost? The price varies widely from <$1 per tonne to >$50 per tonne. The price depends on the type of project, the carbon standard under which it was developed, the location of the offset, and the co-benefits associated with the project.

 There are two types of markets for carbon offsets, compliance and voluntary/

In compliance markets like the European Union (EU), Emission Trading Scheme companies, governments, or other entities buy carbon offsets in order to comply with mandatory and legally binding caps on the total amount of carbon dioxide emissions allowed per year. Failure to comply within compliance markets results in fines or legal penalties. No such regulatory scheme exists in North America.

We have a voluntary market. Within the voluntary market, demand for carbon offset credits is generated by individuals, companies, organizations, etc. who purchase carbon offsets to mitigate their greenhouse gas emissions to meet carbon neutral, net-zero or other established emission reduction goals. 

Because the commercial carbon trade is an emerging market, it’s difficult to judge the quality of offset providers and projects. Trees don’t always live a full life, sequestration projects (for the long-term containment of emissions) sometimes fail and offset companies occasionally deceive their customers.

For those reasons, some environmentalists doubt their validity and effectiveness. Plus voluntary offsets can easily become an excuse for guilt-free overindulgence. Most people aren’t in it to get over on Mother Earth, though.

Carbon offsets do matter because they raise awareness about lowering the greenhouse gas totals worldwide. They work because they get people attuned to the concept of greenhouse gas reduction.

DEEPER DIVE: Wikipedia,, CarbonOffsets.Online, Purchasing Carbon Offsets