GeoLog

Energy, Resources and the Environment

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

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

March 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

While the March headlines might not have been dominated by a particular story, the state of the Earth’s climate has definitely been the overarching theme of the month.

Ahead of World Meteorological Day (celebrate on the 23rd March) the World Meteorological Organization released its annual report on the State of Global Climate. Compiled from a broad range of sources, the report reiterates the findings of the US government agencies NASA and NOAA, who earlier this year declared that 2016 was the warmest year on record.

Not only were temperatures a remarkable 1.1 °C above the pre-industrial period and 0.06 °C above the previous record set in 2015, global sea ice extent dropped more than 4 million square kilometres below average in November. Boosted by a strong El Niño event global sea levels reached record highs too.

The report comes in the wake of US President Trump’s ‘blueprint’ budget for 2018, where he sets out his spending priorities for the year ahead. Nature put together a piece that highlights what US science would stand to lose if the budget is approved. NASA would experience a 0.8% cut from current levels, largely focused on Earth science missions, and future NOAA satellite programmes are also under threat. Worst hit by the cuts would be the Environment Protection Agency (EPA), with a proposed 31% cut in funding, which would “gut EPA programs tackling climate change and pollution”, according to The Guardian.

But the signals are clear: after the record warming in 2016, temperatures have continued to rise in 2017, affecting ecosystems around the world. An example are the corals of the Great Barrier Reef,  which have suffered from widespread bleaching – a situation where they expel their symbiotic algae, meaning they turn white and can die – for the third consecutive year. A new study on mass bleaching of corals was discouraging news: the only long-term solution to the problem is halting global warming. Improving water quality or enforcing fishing controls provides little relief.

But it’s not all bad news when it comes to the global climate and the Earth’s environment. Despite being a record-breaking year in terms of temperatures, 2016 was also the year that saw a dramatic drop in the amount of new coal fueled power plants being built. With cities worldwide battling poor air quality and pollution, this is certainly encouraging news.

What you might have missed

Earlier this month a BBC News crew experienced the fickle nature of volcanoes first hand. The team were visiting Mt. Etna (Sicily) to film a report on volcano monitoring, and  arrived on the Italian island to discover Europe’s most active volcano had just started to erupt again.

Etna’s slow-moving lava is not usually considered dangerous. “But about 20 minutes after arriving, a burst of white steam emerged from the lava – it didn’t make much of a noise or look especially threatening – but the guides started asking people to move. Then, moments later, there was an explosion,” writes Rebecca Morelle, one of the reporters on the team. As they ran down the mountain to safety, the team and tourists, were “pelted with deadly, hot debris.” Read the full account of their ordeal and watch a spectacular video here.

It has also been a big month for palaeontology. Up until now the shape of a dinosaur’s hip determined were along the dinosaur family tree it was placed. Lizard-hipped dinosaurs fell into one group (Saurischia), while those with a more bird-like hip configuration are known as Ornithischia. Now, a team of researchers have proposed a radically new classification system. They found that 21 other anatomical features divide the dinosaurs differently. The new tree puts theropods together with Ornithischian, indicating they probably share a common ancestor. The new theory might face an uphill struggle to debunk the long-lasting consensus on the history of dinosaurs, but many in the field agree that given the thoroughness of the study it is certainly an idea worth considering.

Scientists from the Museum and Cambridge University have proposed radical changes to the dinosaur family tree. Credit: Natural History Museum.

And while we are on the subject of dinosaurs, this brilliant interactive map of every fossil found on Earth (created by @PaleoDB) is a great resource!

Way out in space, the bounty of insights from the Rosetta mission continues. From September 2014, the mission scientists have kept a watchful eye on a 70 m-long, 1 m-wide fracture on the prominent cliff-edge subsequently named Aswan, in the Seth region of the comet, on its large lobe. A few days later, new images of the area revealed that the crack had disappeared and been replaced by a new cliff face, at the bottom of which were many new meter-sized boulders. The discovery allowed the scientists to make the link between the newly created cliff face and outbursts of dust and gas.

You might think the use of infographics to visualise data is a relatively new thing, but you’d be mistaken. This collection of 1800s educational diagrams, of scientific discoveries, from the moon’s surface to the longest rivers, is simply stunning and incredibly effective.

Emslie and Reynolds compare mountains and volcanoes, including mountains in the Alps and Andes. Featured in Geological Diagrams. Courtesy David Rumsey Historical Map Collection

Links we liked

  • Something for the weekend? Why not try your hand at baking a scientifically accurate (sort of!) cake planet?
  • New research suggests that by the middle of the century, more than half of humanity will live in water-stressed areas. Badly managed resources play a crucial role in water shortages globally
  • For a lighthearted, yet very informative, take on mass extinctions this story in The Atlantic is not to be missed
  • A German coal-mine, which has provided power for the country’s industry sector for the past half century, will get a new lease on life when it’s turned into a into a pumped-hydro-storage station, acting like a giant battery that stores solar and wind energy

The EGU story

This time of year, EGU’s biggest story is our annual General Assembly, starting only a few weeks from now. This month, we published the meeting programme, which includes some 1000 sessions and over 17,500 abstracts! On the blog, we published guides on how-to make the best of your oral, poster or PICO presentation at the General Assembly, revealed the finalists of the Communicate Your Science Video Competition, and provided tips on making the most of your time in Vienna without breaking the bank. We look forward to seeing you all in the Austrian capital in the last week of April!

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: harnessing Earth’s inner heat

Imaggeo on Mondays: harnessing Earth’s inner heat

Iceland, the land of ice and fire, is well known for its volcanicity. Most famously, it is home to Eyjafjallajökull: the volcano which caused wide spread mayhem across European airspace when it erupted in 2010.

But not all the local volcanic activity is unwelcome. High temperature geothermal areas are a byproduct of the volcanic setting and the energy released can be used to power homes and infrastructure. Indeed, geothermal power facilities currently generate 25% of the country’s total electricity production.

“I took the photograph during a three hour walk in the Krafla area, a few kilometres away from Myvatn Lake in Northern Iceland,” explains Chiara Arrighi, a PhD student at the University of Florence in Italy, who took today’s featured image while on a two week holiday on the island.

There are 20 high-temperature areas containing steam fields with underground temperatures reaching 250°C within 1,000 m depth dotted across the country. Krafla, a caldera of about 10 km in diameter, and the wider Myvatn area is one of them. The volcano has a long history of eruptions, which drives the intrusion of magma at (geologically) shallow depths which in turn heats groundwater trapped deep underground, generating the steam field. Only a few hundred meters from the shooting location a power station of 60 MW capacity exploits high- and low-pressure steam from 18 boreholes.

Fumaroles and mud pots, like the one photographed by Chiara, are the surface expression of the geothermal activity. The discoloration of the rocks in the immediate vicinity of the bubbling mire is due to the acidic nature of the water in the pool. The steam is rich in hydrogen sulphide, which oxidises to sulphur and/or sulphuric acid as it mixes with oxygen when it reaches the surface. It deposits around the vents of fumaroles and as sulphuric acid in the stagnant waters, leading to alteration of the surrounding bedrock and soil.

If you pre-register for the 2017 General Assembly (Vienna, 22 – 28 April), you can take part in our annual photo competition! From 1 February up until 1 March, every participant pre-registered for the General Assembly can submit up three original photos and one moving image related to the Earth, planetary, and space sciences in competition for free registration to next year’s General Assembly!  These can include fantastic field photos, a stunning shot of your favourite thin section, what you’ve captured out on holiday or under the electron microscope – if it’s geoscientific, it fits the bill. Find out more about how to take part at http://imaggeo.egu.eu/photo-contest/information/.

Imaggeo on Mondays: America’s dead sea

Imaggeo on Mondays: America’s dead sea

On the blog today, Jennifer Ziesch, a researcher at the Leibniz Institute for Applied Geophysics, takes us on a tour of the Great Salt Lake, located in the north of Salt Lake City (Utah). Did you know it is one of the largest salt water lakes in the world?

The large salt lake and Salt Lake City, named after the lake, lie on a flat plain about 1300 m above sea level. The salt lake is bordered to the east by the beautiful high Uinta Mountains (3700 – 4100 m) – part of the Rocky Mountains – and to the west by a huge salt desert, which developed towards the end of the last Ice Age due to dehydration. A semi-arid climate characterizes the landscape of the lake and surrounding area.

Like the Dead Sea, the Great Salt Lake is shrinking rapidly. In the middle of the 19th Century, the lake was almost twice as large as it is today. Mankind diverts the inflow of freshwater from the rivers for agriculture and industry. Local people have reported problems with saline groundwater.

The Great Salt Lake is becoming more salty (up to 27%). How high the salinity is shown in the close-up of a footprint. Salt crystals are formed in their full beauty.

Salt precipitation after a walk near the Great Salt Lake. Credit: Jennifer Ziesch (distributed via imaggeo.egu.eu)

The economy uses the salt and other minerals for fertilisers and wintering products. Unfortunately, the ecosystem is becoming more and more fragile: bird species, crabs and other creatures are losing their habitat.

By Jennifer Ziesch, geoscientist at the Leibniz Institute for Applied Geophysics.

Editor’s note: This text was modified on 14/02/2017 with the addition of an extra photograph to show salt precipitation in the lake. 

If you pre-register for the 2017 General Assembly (Vienna, 22 – 28 April), you can take part in our annual photo competition! From 1 February up until 1 March, every participant pre-registered for the General Assembly can submit up three original photos and one moving image related to the Earth, planetary, and space sciences in competition for free registration to next year’s General Assembly!  These can include fantastic field photos, a stunning shot of your favourite thin section, what you’ve captured out on holiday or under the electron microscope – if it’s geoscientific, it fits the bill. Find out more about how to take part at http://imaggeo.egu.eu/photo-contest/information/.

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