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Imaggeo on Mondays: Erebus Ice Tongue Cave

Imaggeo on Mondays: Erebus Ice Tongue Cave

The interior of this ice cave at the Erebus glacier tongue is cathedral-like. Imagine standing in the cold interior, icy blue stalactites dangling from the cave roof; the sense of awe is overwhelming.

Mt. Erbus is the world’s southernmost active volcano on Ross Island, in Antarctica. Winding its way down its lower slopes is Erebus glacier. Projecting out from the coast, a jagged and thin tongue makes its way into the ice-covered Ross Sea.

The interplay of glacial flow and tides leads to scalloped edges of the tongue where ice caves commonly form. Due to surface melting in the Antarctic summer the interior is filled with intricate icicles and ice crystals.

 

Erebus Ice Tongue. NASA image created by Jesse Allen, using data provided courtesy of NASA/GSFC/METI/ERSDAC/JAROS, and the U.S./Japan ASTER Science Team.

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their photographs and videos to this repository and, since it is open access, these images can be used for free by scientists for their presentations or publications, by educators and the general public, and some images can even be used freely for commercial purposes. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. Submit your photos at http://imaggeo.egu.eu/upload/.

May GeoRoundUp: the best of the Earth sciences from around the web

May GeoRoundUp: the best of the Earth sciences from around the web

Drawing inspiration from popular stories on our social media channels, as well as  unique and quirky research news, this monthly column aims to bring you the best of the Earth and planetary sciences from around the web.

Major Story

In the last couple of weeks of May, the news world was abuzz with the possibility of Donald Trump withdrawing from the Paris Agreement. Though the announcement actually came on June 1st, we’ve chosen to feature it in this round-up as it’s so timely and has dominated headlines throughout May and June.

In withdrawing from the agreement, the United States becomes only one of three countries in rejecting the accord, as this map shows. The implications of the U.S joining Syria and Nicaragua (though, to be clear, their reasons for not signing are hugely different to those which have motivated the U.S withdrawal) in dismissing the landmark agreement have been widely covered in the media.

President Trump’s announcement has drawn widespread condemnation across the financial, political and environmental sectors. Elon Musk, Tesla and SpaceX CEO, was one of many in the business sector to express their criticism of the President’s decision. In response to the announcement, Musk tweeted he was standing down from his duties as adviser to a number of White House councils. While in early May, thirty business CEOs  wrote an open letter published in the Wall Street Journal to express their “strong support for the U.S. remaining in the Paris Climate Agreement.”

In a defiant move, U.S. States (including California, New York and Vermont), cities and business plan to come together to continue to work towards meeting the targets and plans set out by the Paris Agreement. The group, coordinated by former New York City mayor Mark Bloomberg, aims to negotiate with the United Nations to have its contributions accepted to the Agreement alongside those of signatory nations.

“We’re going to do everything America would have done if it had stayed committed,” Bloomberg, said in an interview.

Scientist and learned societies have also been vocal in expressing their criticism of the White House decision. Both Nature and Science collected reactions from researchers around the globe. The EGU, as well as the American Geophysical Union, and many in the broader research community oppose the U.S. President’s decision.

“The EGU is committed to supporting the integrity of its scientific community and the science that it undertakes,” said the EGU’s President, Jonathan Bamber.

For an in-depth round-up of the global reaction take a look at this resource.

What you might have missed

This month’s links you might have missed take us on a journey through the Earth. Let’s start deep in the planet’s interior.

The core generates the Earth’s magnetic field. Periodically, the magnetic field reverses, but what caused it to do so? Well, there are several, competing, ideas which might explain why. Recently, one of them gained a bit more traction. By studying the seismic signals from powerful earthquakes, researchers at the University of Oxford found that regions on top of the Earth’s core sometimes behave like a giant lava lamp. It turns out that blobs of rock periodically rise and fall deep inside our planet. This could affect the magnetic field and cause it to flip.

Meanwhile, at the planet’s surface, the Earth’s outer solid layer (the crust) and upper layer of the molten mantle,  are broken up into a jigsaw of moving plates which pull apart and collide, generating earthquakes, driving volcanic eruptions and raising mountains. But the jury is still out as to when and how plate tectonics started. The Earth is so efficient at recycling and generating new crustal material, through plate tectonics, that only a limited record of very old rocks remains making it very hard to decipher the mystery. A recently published article explores what we know and what yet remains to be discovered when it comes to plate tectonics.

Tectonic plate boundaries. By Jose F. Vigil. USGS [Public domain], distributed by Wikimedia Commons.

Oil, gas, water, metal ores: these are the resources that spring to mind when thinking of commodities which fuel our daily lives. However, there are many others we use regularly, far more often than we realise or care to admit, but which we take for granted. Sand is one of them. In the industrial world it is know as ‘aggregate’ and it is the second most exploited natural resource after water. It is running out. A 2014 United Nations Environment Programme report highlighted that the “mining of sand and gravel greatly exceeds natural renewal rates”.

Links we liked

  • Earth Art takes a whole new meaning when viewed from space. This collection of photographs of natural parks as seen from above is pretty special.
  • This round-up is usually reserved for non-EGU related news stories, but given these interviews with female geoscientists featured in our second most popular tweet of the month, it is definitely worth a share: Conversations on being a women in geoscience – perspectives on what being a female in the Earth sciences.
  • We’ve shared these previously, but they are so great, we thought we’d highlight them again! Jill Pelto, a scientist studying the Antarctic Ice Sheet and an artist, uses data in her watercolous to communicate information about extreme environmental issues to a broad audience.

The EGU story

Temperatures in the Arctic are increasing twice as fast as in the rest of the globe, while the Antarctic is warming at a much slower rate. A new study published in Earth System Dynamics, an EGU open access journal, shows that land height could be a “game changer” when it comes to explaining why temperatures are rising at such different rates in the two regions. Read the full press release for all the details, or check out the brief explainer video, which you can also watch on our YouTube channel.

 

And don’t forget! To stay abreast of all the EGU’s events and activities, from highlighting papers published in our open access journals to providing news relating to EGU’s scientific divisions and meetings, including the General Assembly, subscribe to receive our monthly newsletter.

Imaggeo on Mondays: Polar backbone (Arctic Ocean)

Imaggeo on Mondays: Polar backbone (Arctic Ocean)

This image was taken during the Arctic Ocean 2016(AO16) expedition that ventured to the central regions of the Arctic Ocean, including the North Pole. It shows a pressure ridge, or ice ridge, as viewed from onboard the deck of the icebreaker Oden. It was quite striking that the ice ridge resembled an image of a spine – sea ice being a defining characteristic of the broader Arctic environment and backbone to global climate interactions.

An ice ridge is a wall of broken ice that forms when floating ice is deformed by a build up of pressure between adjacent ice floes. Sea ice can drift quite quickly, and is driven by wind and ocean currents. Ridges are typically thicker than the surrounding level sea ice, being built up by ice blocks of different sizes. The submerged portion of the ridge is referred to as the “keel”, and the part above the water surface is called the “sail”. Ridges can be categorized as “first year” or “multi-year” features, with weathering affecting the morphology.

In the Arctic, such ridges have been measured to in excess of 20 m in thickness including keel and sail. As someone who studies plate tectonics, these collisional boundaries between plates of ice reminded me of a downscaled mountain-building setting.

The AO16 expedition ran from August to September 2016 and involved the Swedish icebreaker Oden and the Canadian icebreaker the Louis S. St-Laurent. A wealth of geological, oceanographic, meteorological data was collected. This period appeared to have coincided with the second lowest extent of sea ice coverage on record (tied with 2007), with around 4.14 million square kilometers.

The geological evolution of the Arctic Ocean in the regions closest to the margins of northern Greenland and the Canadian Arctic Islands are some of the most poorly understood. This is largely a function of the oceanic gyre system, which causes the thickest sea ice to build up in these areas making physical access difficult. From a maritime engineering perspective, the ice ridges pose a challenge and risk to icebreaking operations and navigation. Ice ridges may determine the design load for marine and coastal structures such as platforms, ships, pipelines and bridges, and are important for both ice volume estimations and for the strength of pack ice.

By Grace Shephard, geophysicist from the Centre for Earth Evolution and Dynamics (CEED) at the University of Oslo, Norway.

Heat waves in cities getting worse under climate change

Heat waves in cities getting worse under climate change

The effects of climate change are being felt all over the world but towns and cities are feeling most hot-under-the collar, a new study finds.

Cities are usually warmer than their surroundings due to the urban heat island effect where artificial surfaces absorb more heat than their natural counterparts. Coupled with the loss of the shady effects of trees, urban areas regularly record the hottest temperatures around.

However a study by Dr Hendrik Wouters and colleagues from KU Leuven in Belgium has found that cities are getting even hotter from the effects of climate change with an increase in heat-waves.

Heat-waves are periods of time where temperatures exceed the ‘normal’ high levels. These events are already problematic in urban areas causing power surges, excessive hospitalisations and even deaths.

Wouters and colleagues have investigated how much worse this problem is likely to get as extreme weather events become more common.

Speaking at a press conference at the EGU 2017 General Assembly on 25th April, Wouters said ‘we look at how much temperature levels are exceeding during heat waves‘. Using the expected average temperatures, the climatologists can calculate a threshold of ‘normal’ temperatures and then quantify how often these values are exceeded.

This information was gathered for the whole of Belgium over the 34 years prior to 2015. In rural areas this ‘alarm’ threshold was exceeded at least twice. In urban areas the heat-stress was considerably higher- up to 16 exceedances. Overall, heat-stress was twice as large in cities for the mid 21st century.

Cities (red) show much higher annual degree exceedances than rural areas (green). These exceedances are set increase into the future. (Wouters et al., EGU 2017).

In order to anticipate how much worse this problem might get, the group have modelled heat-stress events for the next 58 years. Wouters was keen to highlight that the severity and frequency of the events is dependent on many factors: ‘There is not only one scenario for the future, it depends on how many greenhouse gases we emit and how much land change will evolve in the future.’

In an extreme scenario, where greenhouse gas emissions and urban growth increase, as many as 25 days in a year could exceed alarm levels by up to 10 degrees celsius. However, if we start to reduce our emissions, the heat-stress problem is likely to stay at current levels.

By Keri McNamara, EGU 2017 General Assembly Press Assistant

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