NASA – A year in the life of Earth’s carbon dioxide

An ultra-high-resolution NASA computer model has given scientists a stunning new look at how carbon dioxide in the atmosphere travels around the globe.

Plumes of carbon dioxide in the simulation shift and swirl as winds disperse the greenhouse gas away from its sources, which are dominated by North American, European and East Asian centres.

The simulation also illustrates differences in carbon dioxide levels in the northern and southern hemispheres and distinct swings in global carbon dioxide concentrations as the growth cycle of plants and trees changes with the seasons.

The carbon dioxide visualisation was produced by a computer model called GEOS-5, created by scientists at NASA Goddard Space Flight Center’s Global Modeling and Assimilation Office.

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Iceland’s Bárðarbunga volcano alert raised to level orange

Volcanic and seismic activity on the island nation of Iceland is nothing new. However as the 2010 eruption of Eyjafjallajökull showed, eruptions in Iceland can have far reaching impacts on the rest of Europe. The 2010 Eyjafjallajökull eruption threw up thousands of tons of ash and dust into the air affecting millions of people and resulting in airspace closures over much of western Europe for a number of days following the eruption.

Iceland's many volcanoes. Bárðarbunga is coloured orange and is located to the south-east of the island. Image source: Icelandic Met Office

Iceland’s many volcanoes. Bárðarbunga is coloured orange and is located to the south-east of the island.
Image source: Icelandic Met Office

The recent unrest took the form of increased earthquake activity starting on Saturday 16th August at Bárðarbunga volcano. The Icelandic Met Office reports that as of Monday 18th around 2600 earthquakes were recorded by local instruments with several events greater than magnitude 3. The strongest event recorded, a magnitude 4.5, occurred on Monday morning. This is the strongest earthquake measured in the region since 1996.

Seismic activity around the volcano as of 20:45 18th August. Event times are colour coded, events larger than magnitude 3 are given as green stars. Source: Icelandic Met Office

Seismic activity around the volcano as of 20:45 18th August. Event times are colour coded, events larger than magnitude 3 are given as green stars.
Source: Icelandic Met Office

The Icelandic Met Office observes very strong indications of ongoing magma movement in the lower crust. As of yet it is uncertain whether there is magma migration to the surface. However if the current activity persists and magma enters shallower portions of the crust then it is likely Bárðarbunga  will erupt. And like Eyjafjallajökull, Bárðarbunga also lies hidden beneath Iceland’s largest glacier. An eruption below the glacier could throw up thousands of tons of steam, ash and dust into the atmosphere and result in similar air traffic disturbances as the 2010 eruptions. Not to mention floods in the local area.

The Icelandic Met Office has raised the risk level to the aviation industry to orange, the second-highest level. An orange alert indicates that the volcano shows heightened or escalating unrest with increased potential of eruption.

The various volcanic alert levels. Bárðarbunga has been raised to level orange. Source: Icelandic Met Office

The various volcanic alert levels. Bárðarbunga has been raised to level orange.
Source: Icelandic Met Office

Various CGS academics and researchers at the University of Leeds are working hard to update the hazard and ground deformation maps of the region around the volcano, as part of the FutureVolc project. This will be invaluable data to monitor the volcano and the eruption, if it occurs.

Ekbal

More information:
[1] The Icelandic Met Office: http://en.vedur.is
[2] A well written and active volcano blog: http://www.wired.com/category/eruptions
[3] http://www.bbc.co.uk/news/world-europe-28843968
[4] http://www.theguardian.com/world/2014/aug/18/iceland-volcano-risk-raised-to-orange
[5] The FutureVolc project website: http://futurevolc.hi.is

How polluted is the air you’re breathing?

air_quality_map-The_Atlantic

The Atlantic has recently published a global map of air quality. Take a look at the interactive map to find out how the quality of the air you’re breathing compares with other countries and cities.The news isn’t good if you’re in China, India, Nepal, Pakistan, and Bangladesh.

The map overlays two sources of data on air pollution: for cities, the World Health Organization’s ambient (outdoor) air pollution in cities database 2014; for countries, ground-level exposures to fine particulate matter (PM2.5) are derived from satellite measures used in the 2014 Environmental Performance Index, a biennial global ranking produced by Yale and Columbia researchers that compares countries on high-priority environmental issues.

Ekbal

More information:
[1] See the interactive on the Atlantic website at
http://www.theatlantic.com/health/archive/2014/06/the-air-we-breathe/372411/
[2] Read more about global air quality at
http://earthobservatory.nasa.gov/Features/AirQuality/?src=fb
[3] Read more about PM2.5 at
http://earthobservatory.nasa.gov/IOTD/view.php?id=82087&src=fb
[4] Find out more about the Environmental Performance Index at
http://epi.yale.edu/our-methods/air-quality

Guest Blog: Man-Made vs. Volcanic Air Pollution

a.schmidtDr Anja Schmidt is an Academic Research Fellow in the Institute for Climate and Atmospheric Science. Her current work involves modelling large-scale, sulphur-rich Icelandic volcanic eruptions. Today she compares the magnitude of man-made air pollution to what the UK could experience during a large Icelandic volcanic eruption

Since the 29 of March, high levels of air pollution are experienced across the UK. Short-term exposure to air pollution has been linked to adverse health effects ranging from an increased risk of suffering asthma attacks, sore or dry throat, sore eyes to more severe effects such as worsening of or needing treatment for pre-existing heart and lung conditions.

On twitter, I was asked to put the current air pollution episode into context with the levels of air pollution that the UK could experience due to a long-lasting volcanic eruption in Iceland. In 2011, Leeds’ researchers published a study showing that a future Laki-type eruption in Iceland could severely degrade air quality across Europe for several months as a result of long-range transport of volcanic gases and particles [download the open access study here]. You might think that volcanic ash would cause all the trouble, but in 1783-1784 Laki pumped as much sulphur dioxide gas into the atmosphere over the course of eight months as all man-made sulphur dioxide emissions globally in 2010! Once sulphur dioxide is in the atmosphere, it gets chemically converted to form tiny sulphuric acid particles – the presence of which will add to the already existing burden of (natural and man-made) particles in the atmosphere. We usually refer to these as “particulate matter” or “PM”. PM2.5 means particles smaller than 2.5 micrometers in diameter – for comparison, a human hair typically has a diameter of 70 micrometers.

Average daily-mean particulate matter mass concentrations (PM2.5) measured in Leeds. The chart has been put together using daily-mean measurements published by DEFRA with the average calculated over the period given in each bar. Volcanic air pollution data are from Schmidt et al. (2011) with the average change in PM2.5 calculated for the north of England based on the first three months of a Laki-type eruption. On a daily basis the amount of volcanic air pollution will vary as a result of wind direction and eruption activity.

Figure 1: Average daily-mean particulate matter mass concentrations (PM2.5) measured in Leeds. The chart has been put together using daily-mean measurements published by DEFRA with the average calculated over the period given in each bar. Volcanic air pollution data are from Schmidt et al. (2011) with the average change in PM2.5 calculated for the north of England based on the first three months of a Laki-type eruption. On a daily basis the amount of volcanic air pollution will vary as a result of wind direction and eruption activity.

 

In Figure 1, I compare the average daily-mean particulate matter concentrations (PM2.5) experienced during man-made and volcanic pollution episodes with background air pollution in Leeds (West Yorkshire, UK). On average, particulate concentrations of 14 μg/m3 are measured in Leeds, which is considered a low level of air pollution on the air quality index devised by DEFRA (Department for Environment, Food and Rural Affairs) to protect public health. Winter- and springtime pollution is generally a little higher (21 μg/m3 on average in 2013) mainly due to stagnant air masses at this time of year. Daily-mean particulate concentrations of 21 μg/m3 are still below the air quality standard of 25 μg/m3 devised by the World Health Organization to protect public health. It is clear from Figure 1 that, in Leeds, the current air pollution episode is already worse than the one the UK experienced in April 2011. In fact, on the DEFRA air quality index the levels of air pollution between 29 March and 3 April 2014 are considered high to very high. On the BBC website you can see that there are already reports of an increase in 999 calls from people experiencing breathing difficulties across the UK.

A Laki-type eruption could last for days to months, and according to my computer model calculations, particulate matter concentrations could, on average, triple in Yorkshire during the first three months of such an eruption. Of course, the level of this additional volcanic pollution would vary on a daily basis mainly due to changes in pollutant transport (wind direction) and eruption activity. Effectively, in Yorkshire and other parts of the UK, we could experience pollution on a similar level as during April 2011 (see Figure 1), but the difference is, of course, that man-made pollution episodes last days to weeks, whereas we could experience volcanic air pollution for several weeks to months.

Pollution reduces visibility. On a ‘clean’ day (left photograph) with particulate matter concentrations (PM2.5) of about 15 μg/m3 one can see tens of kilometres. During April 2011, the UK experiences particulate matter concentrations in excess of 45 μg/m3, which notably reduced visibility to less than five kilometres (right photograph). During the first three months of a Laki-type eruption, particulate matter concentrations experienced in the UK could be of about the same magnitude as in April 2011. The visibility comparison is for illustrative purposes only because visibility reductions for the same change in particulate matter concentrations will depend on relative humidity and chemical composition of the aerosol particles. Photographs taken by K.S. Carslaw (University of Leeds) in April 2011 near Burley in Wharfedale (Yorkshire, UK). Figure modified from Schmidt, A. (in press).

Figure 2: Pollution reduces visibility. On a ‘clean’ day (left photograph) with particulate matter concentrations (PM2.5) of about 15 μg/m3 one can see tens of kilometres. During April 2011, the UK experiences particulate matter concentrations in excess of 45 μg/m3, which notably reduced visibility to less than five kilometres (right photograph). During the first three months of a Laki-type eruption, particulate matter concentrations experienced in the UK could be of about the same magnitude as in April 2011. Photographs taken by K.S. Carslaw (University of Leeds) in April 2011 near Burley in Wharfedale (Yorkshire, UK). Figure modified from Schmidt, A. (in press).

 

High levels of air pollution reduce visibility. In Figure 2, I show two photographs taken from the same viewpoint. The left photograph was taken on a day with low pollution levels (PM2.5 of about 15 μg/m3 as typical for Leeds) and the one on the right was taken on a day with moderate levels of pollution (PM2.5 of about 45 μg/m3 as was measured during the air pollution episodes in April 2011). Visibility is clearly reduced – on a ‘clean’ day one can easily see tens of kilometres far, whereas during the 2011 pollution episode visibility was reduced to less than two kilometres. The air pollution levels in 2011 were of similar magnitude as those we predict for a future Laki-type eruption (Figure 1). Just imagine the public outcry and questions asked if we were to experience several weeks of pollution that is clearly noticeable across several parts of the country. What’s more, imagine what people must have thought is going on in 1783…

In our 2011 study, we used epidemiological evidence to estimate the likely scale of premature mortality due to the increase in particulate matter air pollution due to a Laki-type eruption. We found that in the UK, up to 20,000 people could die prematurely in the first year of a Laki-type eruption. This risk may sound far-fetched and while the probability of a long-lasting eruption such as Laki in Iceland is indeed lower (one event every 200 to 500 years) than that of one of the likes of Eyjafjallajökull in 2010 (one event every five years), its impacts on society may far exceed those we experienced in 2010 after the eruption of Eyjafjallajökull.

 

References:
[1] Schmidt, A., Ostro, B., Carslaw, K.S., Wilson, M., Thordarson, T., Mann, G.W. and Simmons, A. (2011): Excess mortality in Europe following a future Laki-style Icelandic eruption, Proceedings of the National Academy of Sciences, 108, 38, 15710-15715. (download a copy, open access)

[2] Schmidt, A. (in press): Volcanic gas and aerosol hazards from a future Laki-type eruption in Iceland. In: Elsevier Volume #2 of the Hazards, Disaster & Risks Series: Volcanoes

Image

UK Smog Alert and Health Risks From Saharan Dust Storm

A large amount of dust has been blown towards the UK from the Sahara Desert where strong winds have blown up sand into a dust storm.

The video below shows how the dust is blown up and carried to the UK. The dust, shown in pink within the red circle, is carried within clouds, shown in red, to the UK, where it falls within rain showers. (Video from the Met office)

Saharan dust is a contributing factor to air quality as well as pollution levels. The dust brings in pollution from Europe and the high pressure over the UK traps it in place. This has resulted in the highest smog alert warnings for London and much of southern UK.

Air pollution forecast for April 2nd 2014. Purple is very high air pollution, orange moderate and low pollution in green. Source: Defra

Air pollution forecast for April 2nd 2014. Purple is very high air pollution, orange moderate and low pollution in green. Source: Defra

The Department for Environment, Food and Rural Affairs (Defra) said high to very high air pollution was expected across East Anglia, parts of south-east England and around the Humber on Tuesday. High levels of air pollution in parts of the UK are expected to last until the weekend.

Paul Hutcheon at the Met Office said “We usually see this happen several times a year when big dust storms in the Sahara coincide with southerly winds to bring that dust here.”

Defra has warned that adults and children with lung and heart problems, including older people, should avoid excessive strenuous activity for the next week or so. It also warned that “people with asthma may find they use their reliever inhaler more often”.

 

 

 

Defra’s Recommended Health Advice and Actions

Health advice and precautions. Source: Defra

Health advice and precautions. Source: Defra

 

Ekbal

More information:
[1] http://uk-air.defra.gov.uk
[2] http://metofficenews.wordpress.com/2014/03/31/storm-in-sahara-sends-dust-to-uk
[3] http://www.theguardian.com/uk-news/2014/apr/01/london-smog-saharan-dust-storms-downing-street