Geography 2050: the Future of the World Ocean

In this blog post, center postdoc Matthew Costa explains his recent special plenary talk at Geography 2050: the Future of the World Ocean.

When you think of geography, you probably imagine things at superhuman scales across landscapes—extensive mountain ranges, vast basins, and entire continents—and perhaps not plants in a swamp on a coast somewhere. 

Fortunately, the American Geographical Society, host of November’s Geography 2050 event, has kept in mind some seemingly small things like coastal wetlands. And that’s a good thing, because it turns out that mangroves and other coastal vegetated ecosystems, though they may look small on the world map, can play an outsized role in the global battle to counteract human-caused climate change. I was honored and excited to join the group of researchers presenting in Geography 2050: the Future of the World Ocean, in which I discussed the issue of mangrove deforestation worldwide.

As “blue carbon ecosystems,” mangroves sequester carbon. This means that they take CO2 out of the atmosphere and turn it into plant matter via photosynthesis. Some of this organic plant matter, along with some that washes in from other ecosystems, is then buried in their accumulating coastal sediments. These sediments are excellent environments for organic matter preservation, meaning that some carbon takes a one-way trip out of the atmosphere into the ground in these ecosystems.

Mangroves currently cover about 137,000 km2 of the Earth’s surface.  That might sound like a lot, but forests overall cover about 40,000,000 km2 – almost 300 times more area.  But because a given area of mangroves can sequester carbon 100 times more rapidly than the same area of terrestrial forest, each precious hectare of these wetlands represents the best bang for our conservation buck in terms of using natural ecosystems to mitigate climate change through carbon sequestration and storage. 

Unfortunately, mangrove area has been declining in recent decades, with more than 35% lost to deforestation since the mid-20th century.  Given the current climate crisis, the last thing we should be doing is destroying ecosystems that act as natural sinks of atmospheric carbon.  While some governments and research institutions are trying to design systems to remove CO2 from the atmosphere through new technological means, mangroves do it for free.

Mangroves also provide a suite of other ecosystem services, including improving water quality, fostering fisheries and tourism, and protecting coastlines from ocean waves and erosion. Protecting, restoring, and sustainably managing the natural infrastructure that mangroves and other coastal ecosystems provide therefore should be a high priority as we face the challenges of the 21st century.

Want to learn more about the global status of these amazing and valuable ecosystems and the small actions that you and your community can take to be a part of the bigger of the future of our planet? View my full Geography 2050: the Future of the World Ocean lecture here.

Thanks for sharing, Matt!