One of the largest magnetic storms in history quantified: Aurorae covered much of the night sky from the Tropics to the Polar Regions

In early November of this year, aurora borealis were observed at surprisingly low latitudes, as far south as Italy and Texas. Such phenomena indicate the impacts of a solar coronal mass ejection on the Earth's magnetic field and atmosphere. Far more dramatic than this recent light show was, it was nothing compared to a huge solar storm in February 1872. The resulting auroral display from that event ringed the globe and produced auroras observed in sites as close to the equator as Bombay and Khartoum. An international team consisting of scientists from nine counties has now published a detailed study of this historically important event, tracing its solar origin and widespread terrestrial impacts. Telegraph communications were widely disrupted by this storm, but in today's technologically dependent society, such a storm would disrupt power grids and satellite communications. Their findings confirm that such extreme storms are more common than previously thought.

In the modern world, we are increasingly dependent on technological infrastructure such as power grids, communication systems, and satellites.

However, this dependency makes us increasingly vulnerable to the effects of large geomagnetic storms.

"The longer the power supply could be cut off, the more society, especially those living in urban areas, will struggle to cope," Designated Assistant Professor Hayakawa, the lead author of the study, explains.

Such storms could be big enough to knock out the power grid, communication systems, airplanes, and satellites in the worst case.

"Could we maintain our life without such infrastructure?" Hayakawa comments: "Well, let us just say that it would be extremely challenging."

Such extreme storms are rare. In recent studies, two such storms stand out: the Carrington storm in September 1859 and the New York Railroad storm in May 1921.

The new study suggests that another storm, the Chapman-Silverman storm in February 1872, should also be considered as one of these extreme events.

At the time, the storm was big enough to affect the technological infrastructure even in the tropics.

Telegraph communications on the submarine cable in the Indian Ocean between Bombay (Mumbai) and Aden were disrupted for hours.

Similar disturbances were reported on the land line between Cairo and Khartoum.

The multidisciplinary team, consisting of 22 scientists, was led by Nagoya University in Japan (Hisashi Hayakawa), the US National Solar Observatory (Edward Cliver), and the Royal Observatory of Belgium (Frédéric Clette). The 22 researchers used historical records and modern techniques to assess the Chapman-Silverman storm from its solar origin to its terrestrial impacts.

For the solar origin, the group turned to largely forgotten sunspot records from historical archives, especially Belgian and Italian records.

For terrestrial impacts, they used geomagnetic field measurements recorded in places as diverse as Bombay (Mumbai), Tiflis (Tbilisi), and Greenwich to assess temporal evolution and storm intensity.

They also examined hundreds of accounts of visual aurora in different languages caused by the storm.

One of the more interesting aspects of the 1872 storm was that it likely originated in a medium-sized, but complex, sunspot group near the solar disk centre as confirmed by analyses of solar records from Belgium and Italy.

These findings suggest that even a medium-sized sunspot group triggered one of the most extreme magnetic storms in history.

Hayakawa and his colleagues extended their investigations of the historical aurorae by combing through records in libraries, archives, and observatories around the world.

They identified more than 700 auroral records that indicated that the night sky was illuminated by magnificent auroral displays from the polar regions to the tropics (down to ≈ 20° in latitude in both hemispheres).

"Our findings confirm the Chapman-Silverman storm in February 1872 as one of the most extreme geomagnetic storms in recent history. Its size rivalled those of the Carrington storm in September 1859 and the NY Railroad storm in May 1921," Hayakawa said.

"This means that we now know that the world has seen at least three geomagnetic superstorms in the last two centuries. Space weather events that could cause such a major impact represent a risk that cannot be discounted."

Hayakawa said: "Such extreme events are rare. On the one hand, we are fortunate to have missed such superstorms in the modern time. On the other hand, the occurrence of three such superstorms in 6 decades shows that the threat to modern society is real. Therefore, the preservation and analysis of historical records is important to assess, understand, and mitigate the impact of such events."

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Protect delicate polar ecosystems by mapping biodiversity

Polar regions contain vast, undiscovered biodiversity but are both the most-threatened and least-understood areas of the world.

Now scientists led by the University of East Anglia (UEA) and the British Antarctic Survey (BAS) are calling for a roadmap of polar ecosystems to fill that knowledge gap, preserve polar life and even protect "our everyday life and our planet's health." The study would map all biodiversity in those regions, from the atmosphere to the deep sea and from land to the oceans.

The authors said concerted action is required to mitigate the impact of warming on polar ecosystems via conservation efforts, to sustainably manage these unique habitats and their ecosystem services, and for the sustainable bioprospecting of novel genes and compounds for societal gain.

'Multi-omics for studying and understanding polar life', is published today in Nature Communications. The paper is co-authored by UEA, BAS and the University of Bielefeld, Germany.

Polar ecosystems are the most threatened because they are the most sensitive to global warming. They are being lost at a rapid pace and with them all the biology that provides ecosystem services and biology-driven regulation of the climate, including the carbon cycle.

Prof Thomas Mock, Professor of Marine Microbiology in UEA's School of Environmental Sciences, is the joint lead author with Prof Melody Clark, Project Leader for the British Antarctic Survey.

Prof Thomas Mock said: "Biodiversity projections for the polar regions can only be reliably constructed if we have a sufficiently profound understanding of the diversity, ecological functions, and interrelations of polar organisms, as well as their resilience to climate change.

"These remote regions play substantial, often underappreciated, roles in the carbon cycle and drive global nutrient and dissolved organic matter fluxes. Consequently, polar environmental and ecological processes are intimately connected with our everyday life and our planet's health, much of which is underpinned by the endemic biota, from viruses to large animals.

"There is strong evidence that climate-induced changes in the polar regions are already altering species distributions on land and in the sea, with major impacts on ecosystem function."

Some species have shifted poleward, which has a knock-on effect on the food chain. Polar life, from microbes to seals, whales and polar bears, largely depends on overall low temperature and a substantial snow and ice cover, which are experiencing the impacts of global warming.

In the Arctic, temperatures are rising at least four times faster than elsewhere, destabilising the Arctic jet stream and increasing the likelihood of extreme weather events including heat waves, drought and flooding in temperate regions.

On land, permafrost melting and collapsing Arctic coastlines are dramatically altering ecological interactions and biogeochemistry due to the release of millennia-old carbon stores, trace elements, nutrients and potentially even deep-frozen ancient viruses and pathogenic bacteria.

In the oceans, the increased seasonal melting of sea ice is stabilizing surface waters too much, which reduces the amount of nutrients required for primary production to take place.

Similarly, the situation in the Southern Ocean and Antarctic continent is equally bleak, particularly for the Antarctic Peninsula, which has already experienced substantial levels of warming that has increased the loss of sea ice and glaciers.

The Southern Ocean is responsible for the uptake of three-quarters of the anthropogenic heat absorbed by the ocean and up to half of the carbon drawdown. It accounts for around 40 per cent of the global oceanic uptake of anthropogenic CO2 and around 50 per cent of the total atmospheric uptake. Furthermore, sequestering carbon by the organisms living in polar seas is probably the largest natural negative feedback against climate change.

The climate impacts on biodiversity and ecosystem functioning in both the Arctic and Antarctic serve as a bellwether for the consequences of global warming, including the persistence of biodiversity on Earth.

Prof Clark said: "Sequencing technologies have massively changed our abilities to decipher how organisms work. However the uptake in polar biology has been relatively low, especially when considering the tens of thousands of species that reside at the poles and are at threat in our warming world.

"Understanding how lots of very strange organisms living in extreme cold can help answer globally questions and provide real benefits for society. Failure to act now will result in a substantial loss of knowledge regarding evolutionary adaptation to the cold."

Genomic screening not only offers the possibility of identifying populations under stress, but it can also be used for the monitoring of invasive species, thereby facilitating early interventions.

Prof Mock said: "With the cold regions of our planet diminishing, there is a real imperative to obtain full genome sequences for diverse organisms inhabiting polar ecosystems, from the deep oceans to the permafrost on land, for both the Arctic and Antarctic. This will enable the wider application of omics technologies to polar species, which will revolutionise our understanding of evolution in the cold and adaptive responses to a warming world."

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