Could bringing back the mammoths help solve climate change?

Sophia shares her 700 STEM entry where she discusses the potential for woolly mammoths to solve the issue of climate change.

Since Jurassic Park, de-extinction, the process of generating an organism that is either an extinct species or resembles an extinct species, has been an intriguing prospect. The concept of reintroducing the woolly mammoth, for example, has been a well-mooted topic for decades. But many scientists claim it is balderdash. Any investment, they say, risks diverting valuable conservation efforts away from still-living species with little to gain. The business case doesn’t stack up, until now…

Pleistocene park covers 160km2 of perilous tundra in northeast Siberia and forms the basis of Russian scientist Sergei Zimov’s unconventional plan to slow the thawing of the permafrost. Frozen earth, or “Russian Sphinx”, contains over 1600 billion tonnes of carbon, twice the carbon currently in the atmosphere and three times the carbon sequestered in the world’s forests (Schuur, 2019).

As the soil thaws, these carbon-rich vestiges of ancient life, including plant roots and animal carcasses, are released and converted into carbon dioxide and methane by hungry microbes. Scientists predict that at current rates, the thawing of the permafrost will use up to ¼ of our carbon budget set at the Paris Accord (Anon., 2020). This is a slug of the budget we can ill-afford to lose.

Zimov believes he has the answer to averting this potential climate catastrophe; he says, “there is only one [way] to prevent [this] from happening. We must restore the Ice Age.” By reintroducing heavy grazing animals, a feature of the “Pleistocene epoch”, the blanket of metre-thick insulating snow, is trampled, making it dense and more able to allow extreme winter cold to penetrate the soil (Wernick, 2017). Zimov’s early trials are promising: the temperature of the permafrost in Pleistocene park is now 2.2°C lower than before (Anon., 2020). But trampling the snow isn’t the only benefit grazers offer. They also generate a nutrient cycle that favours grasslands over the current tundra flora, a landscape peppered by coniferous trees.

Whilst nurturing grasslands at the expense of trees may seem counter-intuitive in the fight against climate change, the environmental benefits heavily outweigh the costs. Trees may well be good carbon sinks, but they also absorb heat which ultimately warms the permafrost beneath them. Grass on the other hand, reflects more light and thus reduces the amount of heat absorbed by the soil. As well as, capturing more carbon in its roots than current vegetation. In turn, the grasses can feed huge armies of herbivores – a beautifully harmonious ecosystem.

The question is: how do we thin out the trees to help the transition towards this environmental utopia? Rather than a fleet of gas-guzzling bulldozers, perhaps a battalion of climate-friendly, tree-felling mammoths may provide the answer. The problem, of course, is that they are long since extinct. But this might be about to change. George Church, head geneticist on the Harvard Mammoth project thinks so too.

South of Chersky, Siberia, in an area called Duvanny Yar, relics of ancient life lie exposed along the riverbank, including mammoth bones preserved for millions of years by the now-thawed permafrost. Crucially, the sub-zero temperatures largely prevented decomposition of organic material (Mezrich, 2017). Whilst DNA degrades over time, therefore hampering efforts to sequence the entire genome of a mammoth, various fragments of DNA can be stitched together to form a near-complete genomic model. Without the entire genome, cloning is off the table. But there is an alternative: CRISPR technology enables precise editing of DNA within a living organism (Rich, 2020), or, in this context, a close living relative.

99% of a mammoth’s genome is very similar to that of the Asian elephant (Worrall, 2019), and Church is in the process of comparing the Asian elephant’s genome against the model mammoth’s, to identify the genes that need synthesising. The goal is to reintroduce the traits that make a woolly mammoth unique and able to thrive in the sub-Arctic tundra; subcutaneous fat, small ears, a shaggy coat and, importantly, haemoglobin to maintain their high metabolism (Knapton, 2015). Once synthesised, the next step is to place the modified genes into the embryo of its Asian cousin.

According to WWF, in the last 50 years, 60% of the world’s species have disappeared (Grooten, 2018) at the hands of humans. Furthermore, there is growing evidence that we are also responsible for the demise of mammoths. At the point at which humanity’s existence on Earth is itself under threat, isn’t it ironic we turn to a species we helped eradicate to protect the largest carbon reservoir on the planet?

Bibliography

Anon., 2020. The Economist. [Online] Available at: https://www.economist.com/christmas-specials/2020/12/19/one-russian-scientist-hopes-to-slow-the-thawing-of-the-arctic [Accessed February 2021].

Grooten, M. a. A. R., 2018. Living Planet, Gland, Switzerland: WWF.

Knapton, S., 2015. The Telegraph. [Online] Available at: https://www.telegraph.co.uk/news/science/science-news/11488404/Woolly-mammoth-could-roam-again-as-extinct-DNA-merged-with-elephant.html [Accessed February 2021].

Mezrich, B., 2017. Woolly: The True Story of the Quest to Revive One of History’s Most Iconic Extinct Creatures. s.l.:Atria Books.

Rich, F. C., 2020. Zocalo Public Square. [Online] Available at: https://www.zocalopublicsquare.org/2020/11/19/crispr-gene-editing-woolly-mammoth-passenger-pigeon/ideas/essay/ [Accessed February 2021].

Schuur, T., 2019. Permafrost and the Global Carbon Cycle, Flagstaff, Arizona: NOAA Arctic Programme.

Wernick, A., 2017. The World. [Online] Available at: https://www.pri.org/stories/2017-04-30/bold-plan-slow-melt-arctic-permafrost-could-help-reverse-global-warming [Accessed February 2021].

Worrall, S., 2019. National Geographic. [Online] Available at: https://www.nationalgeographic.org/article/we-could-resurrect-woolly-mammoth-heres-how/#:~:text=99%20percent%20of%20their%20genome,not%20cloning%20a%20woolly%20mammo