The unsung hero in the fight against climate change

Buzzword of the day: Climate Change

You will have needed to be living under a rock to have not heard all about the controversial topic of climate change.

Human-induced climate change is having a dramatic effect around the world. In 2017 human-induced warming reached approximately 1°C above pre-industrial levels, with 20–40% of the global human population living in regions that have already experienced warming of more than 1.5°C above pre-industrial in at least one season (IPCC, 2018).

But why should we worry that the world is warming?

Human-induced global warming has already caused multiple observed changes in the climate including more frequent land and marine heatwaves, increases in the frequency, intensity and/or amount of heavy precipitation events, and an increased risk of droughts (IPCC 2018).

So what is causing this problem?

The answer: Greenhouse gases.

The most infamous culprit being carbon dioxide (CO2). At Mauna Loa observatory, a remote research facility located on the slope of Mauna Loa volcano [Hawaii], scientists have been recording atmospheric CO2 levels for the past 60 years and the trends are quite disturbing. Atmospheric CO2 has increased dramatically since recording first began, from 317ppm in 1960 to a high of 415 ppm in May 2019 (NOAA, 2019).

Monthly mean atmospheric carbon dioxide measured at Mauna Loa Observatory, Hawaii

Well maybe seaweed can help..

It is well publicised that trees can remove CO2 from the atmosphere by incorporating the carbon into plant material. But did you know that marine plants can help with storing CO2 from the atmosphere too? Just as with land plants, carbon can be incorporated into marine plants directly or stored in the surrounding sediment. Surprisingly marine plants can even contribute to the long-term storage of carbon in the deep ocean.

Yet it had been assumed that seaweed had little influence in storing CO2 from the atmosphere. In fact seaweed isn’t even included within the Blue Carbon initiative; a global program aiming to lessen climate change through coastal ecosystem management; whereas seagrasses, saltmarshes, and mangroves are. However a recent study published in Nature geoscience challenges this perception. Marine scientists from KAUST have confirmed the importance of seaweed in contributing to deep ocean carbon storage.

Seaweed community at Penguin Island [AU]

Unlike rooted seagrasses and mangroves, the majority of seaweed are rootless and do not remain fixed indefinitely but instead can drift on the currents and tides. This has made estimating their contribution to locking carbon away challenging. However using some cool molecular techniques this study shows that seaweed can be found regularly at depths greater than 1000m. We know that below this depth the carbon is unlikely to return to the atmosphere, and therefore can no longer contribute to the atmospheric CO2.

So it turns out seaweed could have a very important role in helping us fight climate change.

Want to know more? Check out the link below:

or find the published article:

Ortega, A., Geraldi, N.R., Alam, I. et al. Important contribution of macroalgae to oceanic carbon sequestration. Nat. Geosci. 12, 748–754 (2019) doi:10.1038/s41561-019-0421-8

https://rdcu.be/bZzWS


Sources:

IPCC, 2018: Global Warming of 1.5°C. An IPCC Special Report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty [Masson-Delmotte, V., P. Zhai, H.-O. Pörtner, D. Roberts, J. Skea, P.R. Shukla, A. Pirani, W. Moufouma-Okia, C. Péan, R. Pidcock, S. Connors, J.B.R. Matthews, Y. Chen, X. Zhou, M.I. Gomis, E. Lonnoy, T. Maycock, M. Tignor, and T. Waterfield (eds.)]. In Press. https://www.ipcc.ch/sr15/

NOAA (National Oceanic and Atmospheric Administration), Earth System Research Laboratory Global Monitoring Division [online], 5/12/19, Date Accessed: 23/12/19. https://www.esrl.noaa.gov/gmd/ccgg/trends/mlo.html

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