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April GeoRoundUp: the best of the Earth sciences from the 2019 General Assembly

April GeoRoundUp: the best of the Earth sciences from the 2019 General Assembly

The EGU General Assembly 2019 took place in Vienna last month, drawing more than 16,000 participants from 113 countries. This month’s GeoRoundUp will focus on some of the unique and interesting stories that came out of research presented at the Assembly!

Major Stories

Glacial disappearing act in the European Alps

New research from a team of scientists estimated the future of all glaciers within the European Alps, and the results aren’t that hopeful. After running new simulations and analysing observational data, the researchers predict that, if we limit global warming below 2°C above pre-industrial levels, by 2100 glacier volume in the Alps would be roughly two-thirds less than levels seen today.

Furthermore, according to the new research, if we fail to put global warming in check, more than 90 percent of Europe’s glacier volume in the Alps will disappear by the end of the century. “In this pessimistic case, the Alps will be mostly ice free by 2100, with only isolated ice patches remaining at high elevation, representing 5 percent or less of the present-day ice volume,” says Matthias Huss, a researcher at ETH Zurich and co-author of the study.

Evolution of total glacier volume in the European Alps between 2003 and 2100. Credit: Zekollari et al., 2019, The Cryosphere.

The data also suggests that from now until 2050, about 50 percent of the present glacier volume will melt, regardless of how much greenhouse gas emissions we produce in the coming years. This is because glaciers are slow to respond to changes in climate conditions, and still reflect colder climates from the past. In addition to presenting their research at the EGU General Assembly, the team also published the results in The Cryosphere.

The search for the oldest ice announces their drill site

Ice-core extraction near Concordia station (Credit: Thibaut Vergoz, French Polar Institute, CNRS)

After three years of careful consideration, a collection of European ice and climate researchers have pinpointed the spot where they would most likely uncover the oldest ice core possible, one that dates back to 1.5 million years from today.

The consortium of researchers, also known as the Beyond-EPICA project, hopes to pull out a sample of ice containing a seamless record of Earth’s climate history. Such ice samples contain trapped air bubbles, some sealed off thousands to millions of years ago, thus providing undisturbed snapshots into Earth’s ancient atmospheres. Using this climate data, researchers can make predictions on how Earth’s will warm in the future.

At the General Assembly, the scientists formally announced that the drilling operation will be conducted 40 kilometres southwest from the Dome Concordia Station, which is run jointly by France and Italy. The team plans to collect a three km-long ice core from the site, nicknamed ‘Little Dome C,’ over the course of five years, then will spend at least an additional year examining the ice.

Map of Antarctica showing the areas surveyed by BE-OI and the selected drill site (Credit: British Antarctic Survey (BAS))

 

What you might have missed

Predicting the largest quakes on Earth

Scientists have long discussed how intense quakes can be on Earth, with some studies suggesting that Earth’s tectonic features cannot generate earthquakes larger than magnitude 10. However, new research conducted by Álvaro González Center from Mathematical Research in Barcelona, Spain estimates that subduction zones, regions where one tectonic plate is pushed under another, subsequently sinking into the mantle, have the potential to release 10.4 magnitude earthquakes. González’ analysis suggests that such events happen on average every 2,000 years.

“Such events would produce especially large tsunamis and long lasting shaking which would effect distant locations,” Gonzalez said to the Agence France-Presse.

His findings also propose that large asteroid impacts, such as the dinosaur-killing Chicxulub event 66 million years ago, may trigger even larger magnitude shaking. According to data analysis, shaking events reaching magnitude 10.5 or more likely happen on average once every 10 million years.

Where deadly heat will hit the hardest

Heatwaves and heat-related hazards are expected to be more prevalent and more severe as the Earth warms, and a team of researchers looked into which regions of the world will be the most vulnerable.

The scientists specifically analysed human exposure to ‘deadly heat,’ where temperatures as so high that humans aren’t able to cool down anymore. By examining data projections for future population growth and annual days of deadly heat, the researchers assessed which areas will be hit the hardest. They found that, if global warming isn’t limited to 2°C above pre-industrial levels, there will be a few ‘hots spots,’ where large populations are predicted to experience frequent days of deadly heat annually.

Dhaka, Bangladesh, is expected to experience significant exposure to deadly heat in the future, according to research presented at the EGU 2019 meeting. Credit: mariusz kluzniak via Flickr

The research results suggest that future deadly heat will most significantly impact the entire South Asia and South-East Asia region, Western Africa and the Caribbean. Sub-Saharan Africa in particular will experience big increases in deadly heat exposure, due to climate change and population growth.

The researchers also found that a minority of large cities in very poor countries will be the most affected by future heat conditions. “There is a big inequality of who takes the toll of deadly heat,” said Steffen Lohrey, a PhD student at the Technical University Berlin who presented the findings at the EGU meeting.

Europe and the Mediterranean at risk of malaria due to climate change

While malaria was eradicated in Europe and the Mediterranean in the 20th century, there have been an increasing number of new cases in this region of the world, primarily due to international travel and immigration. New research presented at the General Assembly by Elke Hertig, a professor at the University of Augsburg, Germany, suggests that Europe’s future climate may further increase the risk of local malaria recurrence and expansion.

Malaria is transmitted to humans by Anopheles mosquitos and these disease-carrying insects are very sensitive to temperature and precipitation conditions. In particular, these mosquitos thrive in areas with warm spring temperatures and high precipitation in the summer and autumn.

Using climate models, Hertig found that the malaria-carrying mosquito population will likely spread northward as Europe’s climate changes, reaching much of northern Europe by the end of the century. Alternatively, her models suggest that mosquito populations will decline in the Mediterranean regions, mainly due to decreases in summer and autumn rainfall.

A statistical analysis also revealed that, by the end of the century, disease transmission from mosquitoes will be the most effective in southern and south-eastern European regions, including parts of Spain, southern France, Italy, Greece, and the Balkan countries.

Other noteworthy stories

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.

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

July 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 stories  

Signs of water 55 million kilometres away

Last week scientists announced that they have found signs of existing water on Mars, offering new hope to the possibility of uncovering life on the Red Planet’s subsurface.  

Radar observations made by the European Space Agency’s Mars Express satellite, suggest that a liquid lake is buried 1.5 kilometres beneath an ice cap situated near the south pole of Mars. Scientists think that this body of water is likely a few metres deep and 20 kilometres across, “nearly three times larger than the island of Manhattan,” reported Scientific American.

A schematic of how scientists used radar to find what they interpret to be liquid water beneath the surface of Mars. (Credit: ESA)

For the last 12 years the Mars Express satellite has been taking measurements of Mars by sending beams of radar pulses into the planet’s immediate interior. As these waves bounce back, the brightness of the reflection gives information on the material lying beneath Mars’ surface.

The researchers involved came across this discovery while analysing three years worth of data collected by the spacecraft.

“The bluer the colors, the brighter the radar reflection from the material it bounced off. The blue triangle outlined in black in the middle is the purported lake,” reported Science News.

Previous observations, made by NASA’s Curiosity rover for example, have found lake beds on the planet’s exterior, signifying that water may have flowed on Mars in the past. However, if this new finding is confirmed, it would be the first discovery of an existing stable body of water, one of the conditions believed to be necessary for life to thrive.

Context map: NASA/Viking; THEMIS background: NASA/JPL-Caltech/Arizona State University; MARSIS data: ESA/NASA/JPL/ASI/Univ. Rome; R. Orosei et al 2018 (distributed via ESA)

“We are not closer to actually detecting life,” said Manish Patel from the Open University to BBC News, “but what this finding does is give us the location of where to look on Mars. It is like a treasure map – except in this case, there will be lots of ‘X’s marking the spots.”

In their study, published in Science last week, the team remarked, “there is no reason to conclude that the presence of subsurface water on Mars is limited to a single location.”

Northern hemisphere feels the heat

In other news, the two words best describing the northern hemisphere this summer could very well “hot” and “dry,” as a series of heat waves have taken hold of several regions across Europe, Asia, North America and northern Africa. Many countries this month, including Japan, Algeria and Canada, have even experienced record-breaking temperatures.

A look at how this year’s heatwave has changed the colour of our vegetation in just one month (Credit: ESA

For some places, above average temperatures and dry conditions have helped fuel devastating wildfires. More than 50 wildfires have swept through Scandinavian forests this summer, many well within the Arctic Circle, causing Sweden to request emergency aid from nearby countries.

Smoke rises from a wildfire in Enskogen. (Credit: Swedish Environmental Protection Agency/Maja Suslin)

A major wildfire also ignited near Athens, Greece this month, resulting in more than 85 death, with dozens still missing. While Greek officials claim that there are “serious indications” that the flames were brought upon by arson, they also note that the region’s climate conditions were extreme.

To many scientists, this onslaught of hot and dry conditions is a taste of what may soon become the norm.  Of course, these conditions (in Europe, for example) are partly due to weather. “The jet stream – the west-to-east winds that play a big role in determining Europe’s weather – has been further north than usual for about two months,” reports the Guardian, leading to sweltering conditions in the UK and much of Europe, while leaving Iceland cool and stormy.  

However, scientists say that heatwaves in the northern hemisphere are very much linked to global warming. “There’s no question human influence on climate is playing a huge role in this heatwave,” said Myles Allen, a climate scientist at the University of Oxford, to the Guardian in the same article.

A recent assessment on the ongoing heat wave in Europe reports that these conditions are more likely to occur due to climate change. “The findings suggest that rising global temperatures have increased the likelihood of such hot temperatures by five times in Denmark, three times in the Netherlands and two times in Ireland,” said Carbon Brief.

What you might have missed

Geologists have given a name to Earth’s most recent chapter: Meghalayan Age. The announcement was made earlier this month when the International Union of Geological Sciences updated the International Chronostratigraphic Chart, which classifies Earth’s geologic time scale. The new update has divided the Holocene Epoch (the current time series which began 11,700 years ago, when the Earth was exiting its last ice age) into three stages: the Greenlandian, the Northgrippian, and then Meghalayan.

The Meghalayan Age represents the time between now and 4,200 years ago, when a mega-drought led to the collapse of many civilisations across the world. The middle phase, Northgrippian (from 8,300 years ago to 4,200 years ago), is marked by an sudden cooling event brought on by massive glacial melt in Canada that affected ocean currents. Finally the oldest phase, Greenlandian, (from 11,700 years ago to 8,300 years ago) is marked by the end of the last ice age.

The recent update has created some unrest in the geosciences community. “There is still an active debate about assigning a new geologic slice of time to reflect specifically the influence of humans on the planet,” reported BBC News. Some scientists say that the new divisions conflict with the current work being done on proposing a new epoch classification, famously called the ‘Anthropocene,’ which would be marked by the beginning on significant human impact on Earth’s geology and ecosystems.

Links we liked

The EGU story

This month we released not one but two press releases from research published in our open access journals. The findings from both studies have important societal implications. Take a look at them below.

New study: oxygen loss in the coastal Baltic Sea is “unprecedentedly severe”

The Baltic Sea is home to some of the world’s largest dead zones, areas of oxygen-starved waters where most marine animals can’t survive. But while parts of this sea have long suffered from low oxygen levels, a new study by a team in Finland and Germany shows that oxygen loss in coastal areas over the past century is unprecedented in the last 1500 years. The research was published in the European Geosciences Union journal Biogeosciences.

New study puts a figure on sea-level rise following Antarctic ice shelves’ collapse

An international team of scientists has shown how much sea level would rise if Larsen C and George VI, two Antarctic ice shelves at risk of collapse, were to break up. While Larsen C has received much attention due to the break-away of a trillion-tonne iceberg from it last summer, its collapse would contribute only a few millimetres to sea-level rise. The break-up of the smaller George VI Ice Shelf would have a much larger impact. The research was published in the European Geosciences Union journal The Cryosphere.

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.

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

Geosciences Column: Africa’s vulnerability to climate change

Climate change is set to hit the nations of the Global South the hardest.

Ravaged by armed conflicts, a deep struggle with poverty, poor governance and horizontal inequality, some parts of Africa and other Global South regions are arguably the most vulnerable to the impacts of climate change. Largely reliant on natural resources for sustenance, current and future changes in temperatures, precipitation and the intensity of some natural hazards threaten the food security, public health and agricultural output of low-income nations.

Climate change increases heat waves across Africa

Among other impacts, climate change boosts the likelihood of periods of prolonged and/or abnormally hot weather (heat waves). A new study, by researchers in Italy, reveals that in the future all African capital cities are expected to face more exceptionally hot days than the rest of the world.

The new research, published in the EGU open access journal Natural Hazards and Earth System Sciences, has found that extreme heat waves affected only about 37% of the African continent between 1981 to 2005 while in the last decade, the land area affected grew to about 60%. The frequency of heat waves also increased, from an average of 12.3 per year from 1981 to 2005 to 24.5 per year from 2006 to 2015.

By merging information about the duration and the intensity of the recorded heat waves, the authors of the study were able to quantify the heat waves using a single numerical index which they called the Heat Wave Magnitude daily (HWMId). The new measure allowed the team to compare heatwaves from different locations and times.

Geographically plotting the HWMId values for daily maximum temperatures over five-year periods from 1981 to 2015, clearly showed there has been an increase, not only in the number of heat waves and their distribution across the continent, but also an escalation in their intensity (see the figure below). The trend is particularly noticeable since 1996 and peaks between 2011 and 2015.

Heat Wave Magnitude Index daily of maximum temperature (HWMIdtx) for 5-year periods of Global Surface Summary of the Day (GSOD) gauge network records from 1981 to 2015. The bottom-right panes show the spatial distribution of the GSOD station employed in this study. From G. Ceccherini et al. 2016 (click to enlarge).

The figure also highlights that densely populated areas, particularly Northern and Southern Africa, as well as Madagascar, are most at risk.

The rise in occurrences of extreme temperature events will put pressure on already stretched local infrastructure. With the elderly and children most at risk from heat waves, the health care needs of the local population will increase, as will the demand for electricity for cooling. Therefore, further studies of this nature are required, to quantify the implications of African heat waves on health, crops and local economies and assist government officials in making informed decisions about climate change adaptation policies.

Lessons learned from climate adaptation strategies

In the face of weather extremes across Africa including heat waves, droughts and floods, it is just as important to carefully assess the suitability of climate change adaptation policies, argues another recently published study in the EGU open access journal Earth System Dynamics.

Take Malawi, for instance, a severely poor nation: over 74% of the population live on less than a dollar ($) a day and 90% depend on rain-fed subsistence farming to survive. According to Malawi government figures, one-third of the country’s gross domestic product (GDP) comes from agriculture, forestry and fishing.  As a result, the country – and its population – is vulnerable to weather extremes, such as variability in the rainy season, prolonged dry spells and rise in the number of abnormally hot days.

A 2006 Action Aid report states that “increased droughts and floods may be exacerbating poverty levels, leaving many rural farmers trapped in a cycle of poverty and vulnerability. The situation in Malawi illustrates the drastic increases in hunger and food insecurity being caused by global warming worldwide.”

The Lake Chilwa Basin Climate Adaptation Programme (LCBCCAP) aims to enhance the resilience of rural communities surrounding Lake Chilwa to the impacts of droughts, floods and temperature extremes. The lake is a closed drainage lake (meaning it relies on rainfall to be replenished) in the south eastern corner of Malawi.

Perceptions of how climate change affects residents of the Lake Chilwa Basin. From H. Jørstad and C. Webersik, 2016 (click to enlarge).

The authors of the Earth System Dynamics study interviewed a group of 18 women (part of the LCBCCAP programme), back in early 2012, to understand how they perceived they were affected by climate change and whether the adaptation tools provided by the programme would meet their long-term needs.

The women agreed unanimously: climate in the Lake Chilwa Basin was changing. They reported that rainy seasons had become shorter and more unreliable, leading to droughts and dry spells. One of the women mentioned raising temperatures and fewer trees, due to overexploitation.

All those interviewed were part of the women fish-processing group, an initiative which sought to provide an alternative income for the women as traditional agricultural activities became unreliable due to erratic rainfall and prolonged dry seasons.

While the women’s new occupation did provide economic relief, the study authors highlight that the group’s new source of income was just as dependant on natural resources as agriculture.

Throughout the interviews, the women of the fish-processing group expressed concerns that the they thought Lake Chilwa might dry up completely by 2013.

“Yes, the lake will dry up and I will not have a business,” says Tadala, one of the women interviewed in the study. While another local woman said “Yes, lower water levels in the lake is threatening my business.”

Lake Chilwa has a long history of drying up: in the last century it has dried up nine times.  If the lake dried up completely, the women of the fish-processing group would be out of business for 2 to 4 years. Even small drops in the water level affect the abundance of fish stocks.

Lake Chilwa has a history of drying up. These Landsat images show the net reduction of lake area between October 1990 and November 2013. show changes to the extensive wetlands (bright green) that surround Lake Chilwa. These wetlands are internationally recognized as an important seasonal hosting location for migratory birds from the Northern Hemisphere. Credit: USGS

The interviews were carried out in early 2012. The previous two years had seen very limited rainfall. Not enough to sustain the lake, but the situation, at the time of the interviews wasn’t critical. However, throughout the summer of 2012 the lake water levels started falling rapidly prompting the relocation of large groups of lakeshore residents. Those dependant on fishing to support their families were most affected.

The women fish-processing group is a good demonstration of how local communities can adopt low-cost measures to adjust to climate change. At the same time, it highlights the need to assess climate adaptation strategies to take into consideration whether they too are dependent on climate-sensitive natural resources. The new research argues that diversifying people’s livelihoods might provide better long-term coping mechanisms.

By Laura Roberts Artal, EGU Communications Officer

References and resources

Ceccherini, G., Russo, S., Ameztoy, I., Marchese, A. F., and Carmona-Moreno, C.: Heat waves in Africa 1981–2015, observations and reanalysis, Nat. Hazards Earth Syst. Sci., 17, 115-125, doi:10.5194/nhess-17-115-2017, 2017

Jørstad, H. and Webersik, C.: Vulnerability to climate change and adaptation strategies of local communities in Malawi: experiences of women fish-processing groups in the Lake Chilwa Basin, Earth Syst. Dynam., 7, 977-989, doi:10.5194/esd-7-977-2016, 2016.

ActionAid: Climate change and smallholder farmers in Malawi: Understanding poor people’s experience in climate change adaptation, ActionAid International, 2006.

NASA: The consequences of climate change

United States Environmental Protection Agency (EPA): Understanding the Link Between Climate Change and Extreme Weather

National Oceanographic and Atmospheric Administration (NOAA): Heat wave, a major summer killer