ticking

Permafrost covers about a quarter of the landmass in the Northern Hemisphere. It stores vast quantities of organic carbon in the form of dead plant matter. As long as it stays frozen, it is no threat to the climate. But as it thaws, microorganisms start breaking down that plant matter and large amounts of carbon are released into the atmosphere in the form of carbon dioxide and methane.

This process has often been described as a ticking timebomb for the climate. The theory is that once global warming reaches a certain level, the process will become self-amplifying setting off a catastrophic amount of warming. If that level was reached, it would be a tipping point in the changing climate.

An international research team from the Alfred Wegener Institute in Germany has extensively researched this hypothesis. Their conclusion is that within the permafrost, there are multiple geological, hydrological, and physical processes that are self-amplifying and, in some cases, irreversible. However, these processes act only locally or regionally. There is no evidence that some particular threshold in global warming could affect all permafrost and accelerate its thawing on a global level.

This research does not mean that Arctic permafrost is nothing to worry about. In fact, there are ways in which it is more worrisome. Because the permafrost is very heterogenous – meaning it is very different in different places – there will be numerous small, local tipping points that will be exceeded at different times and at different levels of warming. All of this will proceed in step with global warming, contributing to the overall worsening situation. There is no warming level below which permafrost thawing is not a problem.

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Thawing permafrost: Not a climate tipping element, but nevertheless far-reaching impacts

Photo, posted January 24, 2014, courtesy of Brandt Meixell / USGS via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

There are only two northern white rhinos left in the world, and both of them are female. The last male died in 2018. Northern white rhinos live to about 40 and one of the two remaining is 35 and the other 24. The clock is ticking for the species.

Recently, scientists with the BioRescue consortium successfully used in vitro fertilization to impregnate a southern white rhino. It was the world’s first IVF rhino pregnancy.

There is now some hope that IVF could be used to produce more northern white rhinos. For various medical reasons, neither of the remaining two female rhinos can serve as a surrogate mother. But there is a plan B.

For a number of years, BioRescue has been creating northern white rhino embryos with eggs from the remaining females and sperm that was collected from males before they died. There are now 30 northern white rhino embryos in cold storage, and they are continuing to produce more.

The recent success with the southern white rhino IVF provides hope that southern white rhino females can act as surrogate mothers with implanted northern white rhino embryos. The species are similar enough that it should work.

The plan is to select surrogates and implant them. This should happen this year. A rhino pregnancy lasts 16 months. If this is successful, there could be northern white rhino babies in two or three years. The scientists want the offspring to live with the surviving northern whites for years to learn the social behavior of its kind.

It is possible that these gentle, hulking creatures may get a new lease on life.

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Just two northern white rhinos are left on Earth. A new breakthrough offers hope

Photo, posted September 16, 2017, courtesy of San Diego Zoo Safari Park via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio