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The art of turning climate change science to a crochet blanket

The art of turning climate change science to a crochet blanket

We welcome a new guest post from Prof. Ellie Highwood on why she made a global warming blanket and how you could the same!

What do you get when you cross crochet and climate science?
A lot of attention on Twitter.
At the weekend I like to crochet. Last weekend I finished my latest project and posted the picture on Twitter. And then had to turn the notifications off because it all went a bit noisy. The picture of my “global warming blanket” rapidly became my top tweet ever, with more retweets and likes than anything else. Apparently I had found a creative way to visualise trends in global mean temperature. I particularly liked the “this is the most frightening knitwear I have seen all year” comment. Given the interest on Twitter I thought I had better answer a few of the questions in a blog post. Also, it would be great if global warming blankets appeared all over the world.

How did you get the idea?
The global warming blanket was based on “temperature” blankets made by crocheters around the world. Their blankets consist of one row, or square, of crochet each day, coloured according to the temperature at their location. They look amazing and show both the annual cycle and day-to-day variability. Other people make “sky” blankets where the colours are based on the sky colour of the day – this results in a more muted grey-blue-white colour palette.
I wondered what the global temperature series would look like as a blanket. Also, global warming is often explained as greenhouse gases acting like a blanket, trapping infrared radiation and keeping the Earth warm. So that seemed like an interesting link. I also had done several rainbow themed blankets in the past and had a lot of yarn left that needed using.

Where did the data come from?

I used the annual and global mean temperature anomaly compared to 1900-2000 mean as a reference period as available from NOAA. This is what the data looks like shown more conventionally.

Global temperature anomalies (source: NOAA)

I then devised a colour scale using 15 different colours each representing a 0.1 °C data interval. So everything between 0 and 0.099 was in one colour for example. Making a code for these colours, the time series can be rewritten as in the table below. It is up to the creator to then choose the colours to match this scale, and indeed which years to include. I was making a baby sized blanket so chose the last 100 years, 1916-2016.

Because of these choices, and the long reference period, much of the blanket has relatively muted colour differences that tend to emphasise the last 20 years or so. There are other data sets available, and other reference periods and it would be interesting to see what they looked like. Also the colours I used were determined mainly by what I had available; if I were to do another one, I might change a few around (dark pink looks too much like red in the photograph and needed a darker blue instead of purple for the coldest colour), or even use a completely different colour palette – especially as rainbow colour scales aren’t great as they can distort data and render it meaningless if you are colour blind. Ed Hawkins kindly provided me with a more user friendly colour scale which I love and may well turn into a scarf for myself (much quicker than a blanket!).

#endrainbow colour scale (from E. Hawkins)

How can I recreate this?
If you want to create something similar, you will need 15 different colours if you want to do the whole 1850-2016 period. You will need relatively more yarn in colours 3-7 than other colours (if, like me you are using your stash). You can use any stitch or pattern but since you want the colour changes to be the focus of the blanket, I would choose something relatively simple. I used rows of treble crochet (UK terms) and my 100 years ended up being about 90 cm by 110 cm. You can of course choose any width you like for your blanket, or make a scarf by doing a much shorter foundation row. It goes without saying that it could also be knitted. Or painted. Or woven. Or, whatever your particular craft is.

If you look closely (check out arrows on the figure at the top) you can see the 1997-1998 El Nino (relatively warm yellow stripe amongst the pink – in this photo the dark pink looks red – I might change this colour if I did it again), 1991/92 Pinatubo eruption (relatively cool pink year) as well as cool periods 1929, and 1954-56 and the relatively warm 1940-46. Remember that these are global temperature anomalies and may not match your own personal experience at a given location!

Table with the colour codes used to make the global warming blanket

How long did it take?
I used a very simple stitch, so for a blanket this size, it was a couple of months (note I only crochet in the evenings 2 or 3 evenings a week for a couple of hours with more at some weekends). It helped that the Champions League was on during this time as other members of the household were happy to sit around watching football whilst I crocheted. Weave the ends in as you go. There are a lot of them, and I had to do them all at the end. The time flies because….

Why do I crochet?
I like crochet because you can do simple projects whilst thinking about other things, watching TV or listening to podcasts, or, you can do more complicated things which require your full attention and divert your brain from all other things. There is also something meditative about crochet, as has been discussed here. I find it a good way to destress. Additionally, a lot of what I make is for gifts or for charities and that is a really good feeling.

What’s next?
Suggestions have come in for other time series blankets e.g. greys for aerosol optical depth punctuated by red for volcanic eruptions, oranges and yellows punctuated by black for solar cycle (black being high sun spot years), a central England temperature record. Blankets take time, but scarves could be quicker so I might test a few of these ideas out over the next few months. Would love to hear and see more ideas, or perhaps we could organise a mass “global warming blanket” make-athon around the world and then donate them to communities in need.

And finally.
More seriously, whilst lots of the initial comments on Twitter were from climate scientists, there are also a lot from a far more diverse set of folks. I think this is a good example of how if we want to reach out, we need to explore different ways of doing so. There are only so many people who respond to graphs and charts. And if we can find something we are passionate about as a way of doing it, then all the better.

This is post has also been published here.

Edited by Dasaraden Mauree


Ellie Highwood is Professor of Climate Physics in the Department of Meteorology at the University of Reading. She did a Bsc in Physics at the University of Manchester before studying for a PhD at Reading, where she has been ever since! Her research interests concern the role of atmospheric particulates (aerosol) in climate and climate change. She has led two international aircraft campaigns to measure the properties of aerosol and has been involved in many others. Research projects have considered Saharan dust, volcanoes, and aerosols from human activities. She has over 40 publications in the peer reviewed literature and a few media appearances. She also teaches introductory meteorology and climate change to undergraduates, and project management to PhD students. Previously she has been a member of RMetS Council and Education Committee, and Editor of Society News. She also writes a regular “climate scientist” column for the Weather magazine. She tweets as @EllieHighwood.

What? Ice lollies falling from the sky?

What? Ice lollies falling from the sky?

You have more than probably eaten many lollipops as a kid (and you might still enjoy them. The good thing is that you do not necessarily need to go to the candy shop to get them but you can simply wait for them to fall from the sky and eat them for free. Disclaimer: this kind of lollies might be slightly different from what you expect…


Are lollies really falling from the sky?

Eight years ago (in January 2009), a low-pressure weather system coming from the North Atlantic Ocean reached the UK and brought several rain events to the country. Nothing is really special about this phenomenon in Western Europe in the winter. However, a research flight started sampling the clouds in the warm front (transition zone where warm air replaces cold air) ahead of the low-pressure system and discovered hydrometeors (precipitation products, such as rain and snow) of an unusual kind. Researchers named them ‘ice lollies’ due to their characteristic shape and maybe due to their gluttony. The microphysical probes onboard the aircraft, combined with a radar system located in Southern England, allowed them to measure a wide range of hydrometeors, including these ice lollies that were observed for the first time with such concentration levels.

How do ice lollies form?

A recent study (Keppas et al, 2017) explains that ice lollies form when water droplets (size of 0.1 to 0.7 mm) collide with ice crystals with the form of a column (size of 0.25 to 1.4 mm) and freeze on top of them (see Fig. 2).

Fig 2: Formation of an ice lolly: water droplet (the circle) collides with an ice crystal (the column) [Credit: Fig. 1a from Keppas et al., (2017)].

Such ice lollies form in ‘mixed-phase clouds’, i.e. clouds made of water droplets and ice crystals and whose temperature is below the freezing point (0°C). At these temperatures, water droplets can be supercooled, meaning that they stay liquid below the freezing point.

Figure 3 below shows the processes and particles involved in the formation of ice lollies. Ice lollies are mainly found at temperatures between 0 and -6°C, in the vicinity of the warm conveyor belt, which represents the main source of warm moist air that feeds the low-pressure system. This warm conveyor belt brings water vapour that participates in the formation and growth of supercooled water droplets. Ice crystals formed near the cloud tops fall through the warm conveyor belt and collide with the water droplets to form ice lollies.

Fig 3: Processes involved with the formation of ice lollies, which mainly form under the warm conveyor belt [Credit: Fig 4 from Keppas et al., (2017)].

Are these ice lollies important?

Ice lollies were observed more recently (September 2016) during another aircraft mission over the northeast Atlantic Ocean but no radar coverage supported the observations. At the moment of writing this article, the lack of observations prevent us from determining the importance of these ice lollies in the climate system. However, future missions would provide more insight. In the meantime, we suggest you to enjoy a lollipop such as the one shown in the image of this week 🙂

This is a joint post, published together with the Cryospheric division blog, given the interdisciplinarity of the topic.

Edited by Sophie Berger and Dasaraden Mauree

Reference/Further reading

Keppas, S. Ch., J. Crosier, T. W. Choularton, and K. N. Bower (2017), Ice lollies: An ice particle generated in supercooled conveyor belts, Geophys. Res. Lett., 44, doi:10.1002/2017GL073441

 


DavidDavid Docquier is a post-doctoral researcher at the Earth and Life Institute of Université catholique de Louvain (UCL) in Belgium. He works on the development of processed-based sea-ice metrics in order to improve the evaluation of global climate models (GCMs). His study is embedded within the EU Horizon 2020 PRIMAVERA project, which aims at developing a new generation of high-resolution GCMs to better represent the climate.

Black Carbon: the dark side of warming in the Arctic

Black Carbon: the dark side of warming in the Arctic

When it comes to global warming, greenhouse gases – and more specifically CO2 – are the most often pointed out. Fewer people know however that tiny atmospheric particles called ‘black carbon’ also contribute to the current warming. This post presents a paper my colleague and I recently published in Nature Communications . Our study sheds more light into the chemical make-up of black carbon, passing through the Arctic.


Black Carbon warms the climate

 Figure 1: Global radiative forcing of CO2 (green) compared to black carbon (blue). The colored bars show the mean change in radiative forcing due to the concentration of CO2 and BC in the atmosphere. The estimated range for the expected radiative forcing is everything between the white lines, which show the 90% confidence interval. (Data according to Boucher et al. 2013 (IPCC 5th AR) and Bond et al. 2013). [Credit: Patrik Winiger]

Figure 1: Global radiative forcing of CO2 (green) compared to black carbon (blue). The colored bars show the mean change in radiative forcing due to the concentration of CO2 and BC in the atmosphere. The estimated range for the expected radiative forcing is everything between the white lines, which show the 90% confidence interval. (Data according to Boucher et al. 2013 (IPCC 5th AR) and Bond et al. 2013). [Credit: Patrik Winiger]

Black Carbon (BC) originates from incomplete combustion caused by either natural (e.g., wild fires) or human (e.g., diesel car emissions) activities. As the name suggests, BC is a dark particle which absorbs sunlight very efficiently. In scientific terms we call this a strong positive radiative forcing, which means that the presence of BC in the atmosphere is helping to heat the planet. Some estimates put its radiative forcing in second place, only after CO2 (Figure 1). The significant thing about BC is that it has a short atmospheric lifetime (days to weeks), meaning we could quickly avoid some climate warming by getting rid of its emissions. Currently global emissions are increasing year by year and on snow and ice, the dark particles have a longer lasting effect due to the freeze and thaw cycle, where BC can re-surface, before it is washed away. It is important however to note, that our main focus on emission reduction should target (fossil-fuel) CO2 emissions, because they will affect the climate long after (several centuries) they have been emitted.

Arctic amplification: strongest warming in the North Pole

The Arctic is warming faster than the rest of our planet. Back in 1896, the Swede Arrhenius, (better known for his works: in chemistry), calculated, that a change in atmospheric CO2 – which at that time was a good 100 ppm lower than today – would change the temperature at higher latitudes (towards the poles) more than at lower latitudes.

Figure 2: Observation based global surface temperature anomalies for Jan-Mar (2016) in °C with respect to a 1961-1990 base year. Credit: GISTEMP Team, 2016: GISS Surface Temperature Analysis (GISTEMP). NASA Goddard Institute for Space Studies. Dataset accessed 2016-10-15 at http://data.giss.nasa.gov/gistemp/ [Hansen et al., 2010].

Figure 2: Surface temperature anomalies (in °C) for Jan-Mar (2016) with respect to a 1961-1990 baseline. [ Credit: NASA — GISTEMP (accessed 2016-10-15) and Hansen et al., 2010].

The problem with his calculations – as accurate and impressive they might have been – was, that he ignored the earth’s geography and seemed unaware of the big heat capacity of the oceans. On the southern half of our planet there is a lot more water, which can take up more heat, as compared to the northern half with more land surface. Thus, in reality the latitudes on the southern hemisphere have not heated as much as their northern counterparts and this effect came to be known as Arctic amplification.

Dark particles on bright snow and ice

Figure 3: Welcome to the Greenland Ice Sheet everybody. Probably an extreme case of ice covered in cryoconite, captured in August 2014 [Credit: Jason Box, (LINK: http://darksnow.org/)].

Figure 3: Ice covered in cryoconite, Greenland Ice Sheet, in August 2014 [Credit: Jason Box — Dark Snow project].

Greenhouse gases and BC are not the only reasons for the increase in temperature change and earlier onset of the melting season in the Arctic. Besides BC, there are other ‘light absorbing impurities’ such as dust, microorganisms, or a mixture of all of the above, better known as cryoconite. They all absorb solar radiation and thus decrease the albedo – the amount of solar energy reflected back to space – of the underlying white surface. This starts a vicious cycle by which these impurities melt the snow or ice and eventually uncover the usually much darker surface (e.g., rock or open sea water), leading to more solar absorption and the cycle continues. The effect and composition of these impurities are currently intensively studied on the Greenland ice sheet (check out the Black and Bloom, as well as the Dark Snow projects).

Black Carbon effect on climate is highly uncertain

One of the reasons for the high uncertainty of BC’s climate effects is the big range in effects it has (see white line on Figure 1), when it interacts with snow and ice (or clouds and the atmosphere).

Another source of uncertainty is probably the big estimated range in the global, and especially in the regional emissions of BC in the Arctic. For example, the emission inventory we work with (ECLIPSE), is based on international and national statistics that indicate how much of a certain fuel (diesel, coal, gas, wood, etc.) is used, and in which way it is used (vehicle sizes, machine type and age, operating conditions, etc.). These numbers can vary a lot. If we, for example, line up different emission inventories of man-made emissions (Figure 4), by comparing the two different fractions of BC (fossil fuels vs. biomass burning) at different latitudes, then we see that the closer we get to the North pole, the more these emission inventories disagree. And this is still ignoring atmospheric transport or emissions of natural sources, such as wildfires.

Computer models, necessary to calculate global climate change, are partly based on input from these emission inventories. Models used for the calculation of the transport of these tiny particles have vastly improved in recent years, but still struggle at accurately mimicking the seasonality or extent of the observed BC concentrations. To some extent this is also due to the range of parametrization in the model, mainly the lifetime of BC, including its removal from the atmosphere by wet scavenging (e.g., rain). So to better understand black carbon effects on climate, more model calculations are necessary, for which the emission inventory estimates need to be verified by observations.

Figure 4: Fraction biomass burning of BC (fbb) at different latitudes North, estimated by three different emission inventories. The green line shows the GAINS emission inventory, which was the precursor to the ECLIPSE inventory (Klimont et al. 2016) [Credit: Patrik Winiger]

Figure 4: Fraction biomass burning of BC (fbb) at different latitudes North, from three different emission inventories. The green line shows the GAINS emission inventory, which was the precursor to the ECLIPSE inventory (Klimont et al. 2016) [Credit: Patrik Winiger]

How do we trace the origin of black carbon?

This is where the science of my colleagues and me comes in. By looking at BC’s isotopic ratio of stable-carbon (12C/13C) and its radiocarbon (14C) content we were able to deduce information about the combustion sources (Figure 5).

Plants (trees) take up contemporary radiocarbon, naturally present in the atmosphere, by photosynthesis of atmospheric CO2. All living organisms have thus more or less the same relative amount of radiocarbon atoms, we talk of a similar isotopic fingerprint. BC from biomass (wood) burning thereby has a contemporary radiocarbon fingerprint.

When they die, organisms stop incorporating contemporary carbon and the radiocarbon atoms are left to decay. Radiocarbon atoms have a relative short (at least on geological time-scales) half-life of 5730 years, which means that fossils and consequentially BC from fossil fuels are completely depleted of radiocarbon. This is how the measured radiocarbon content of a BC sample gives us information on the relative contributions of fossil fuels vs. biomass burning.

The stable carbon isotopic ratio gives information on the type of combustion sources (liquid fossil fuels, coal, gas flaring or biomass burning). Depending on how a certain material is formed (e.g., geological formation of coal), it has a specific isotopic ratio (of 12C/13C), like a fingerprint. Sometimes isotopic fingerprints can be altered during transport (because of chemical reactions or physical processes like condensation and evaporation). However, BC particles are very resistant to reactions and change only very little. Hence, we expect to see the same fingerprints at the observation site and at the source, only that the isotopic signal at the observation site will be a mixture of different source fingerprints.

Figure 5/ Carbon isotopic signatures of different BC sources, summarized by E.N. Kirillova (2013).

Figure 5: Carbon isotopic signatures of different BC sources, summarized by E.N. Kirillova (2013). To give information about the isotopic fingerprint, the delta-notation is used (small delta for 12C/13C, and big delta for 12C/14C). The isotopic values show how much a certain sample is different, on a per mil scale, from an international agreed isotopic standard value (or ratio) for carbon isotopes. [Credit: fig 1 from Kirillova (2013)]

Where does the black carbon in European Arctic come from?

In our study (Winiger et al, 2016), we observed the concentrations and isotopic sources of tiny particles in airborne BC for over a year, in the European Arctic (Abisko, Sweden), and eventually compared these observations to model results, using the freely available atmospheric transport model FLEXPART and emission inventories for natural and man-made BC emissions.

Seeing our results we were first of all surprised at how well the model agreed with our observations. We saw a clear seasonality of the BC concentrations, like it has been reported in the literature before, and the model was able to reproduce this. Elevated concentrations were found in the winter, which is sometimes referred to as Arctic haze. The combustion sources showed a strong seasonality as well. The radiocarbon data showed, that fossil fuel combustion dominated in the winter and (wood) biomass burning during the low BC-burden periods in the summer. With a combination of the stable isotope fingerprints and Bayesian statistics we further concluded, that the major fossil fuel emissions came from liquid fossil fuels (most likely diesel). The model predicted a vast majority of all these BC emissions to be of European origin. Hence, we concluded, that the European emissions in the model had to be well constrained and the model parametrization of BC lifetime and wet-scavenging had to be fairly accurate for the observed region and period. Our hope is now that our work will be implemented in future models of BC effects and taken into account for future BC mitigation scenarios.

Figure 6: This is an example from the model calculations, showing where the (man-made) BC came from in January 2012. Abisko's position is marked as a blue star. The darker (red) spots show sources of higher BC contribution. This winter example was among the three highest observed (in terms of BC concentration) and the sources were ~50% wood burning, ~20% liquid fossil fuels (diesel) and ~30% coal. Some of the darkest spots can clearly be attributed to European cities.

Figure 6: Example from the model calculations, showing where the (man-made) BC came from in January 2012. Abisko’s position is marked as a blue star. The darker (red) spots show sources of higher BC contribution. This winter example was among the three highest observed (in terms of BC concentration) and the sources were ~50% wood burning, ~20% liquid fossil fuels (diesel) and ~30% coal. Some of the darkest spots can clearly be attributed to European cities. [Credit: fig4b from Winiger et al (2016)]

References

  • Anderson, T. R., E. Hawkins, and P. D. Jones (2016), CO2, the greenhouse effect and global warming: from the pioneering work of Arrhenius and Callendar to today’s Earth System Models, Endeavour, in press, doi:10.1016/j.endeavour.2016.07.002.
  • Arrhenius, S. (1896), On the influence of carbonic acid in the air upon the temperature of the ground., Philos. Mag. J. Sci., 41(August), 239–276, doi:10.1080/14786449608620846.
  • Hansen, J., R. Ruedy, M. Sato, and K. Lo (2010), Global surface temperature change, Rev. Geophys., 48(4), RG4004, doi:10.1029/2010RG000345.
  • Klimont, Z., Kupiainen, K., Heyes, C., Purohit, P., Cofala, J., Rafaj, P., Borken-Kleefeld, J., and Schöpp, W.: Global anthropogenic emissions of particulate matter including black carbon, Atmos. Chem. Phys. Discuss., doi:10.5194/acp-2016-880, in review, 2016.
  • Kirillova, Elena N. “Dual isotope (13C-14C) Studies of Water-Soluble Organic Carbon (WSOC) Aerosols in South and East Asia.” (2013). ISBN 978-91-7447-696-5 pp. 1-37
  • Winiger, P., Andersson, A., Eckhardt, S., Stohl, A., & Gustafsson, Ö. (2016). The sources of atmospheric black carbon at a European gateway to the Arctic. Nature Communications, 7.

Edited by Sophie Berger, Dasaraden Mauree and Emma Smith
This is joint post with the Cryospheric Division , given the interdisciplinarity of the topic featured.


portraitPatrik Winiger is a PhD student at the Department of Environmental Science and Analytical Chemistry and the Bolin Centre for Climate Research, at Stockholm University. His research interest focuses on impact and mitigation of Short Lived Climate Pollutants and anthropogenic CO2 emissions. Currently he investigates the sources of black carbon aerosols in the Arctic. He tweets as @PatrikWiniger

 

Science Communication – Brexit, Climate Change and the Bluedot Festival

Science Communication – Brexit, Climate Change and the Bluedot Festival

Earlier this summer journalists, broadcasters, writers and scientists gathered in Manchester, UK for the Third European Conference of Science Journalists (ECSJ) arranged by two prestigious organisations. Firstly, the Association of British Science Writers (ABSW) who provides support to those who write about science and technology in the UK through debates, events and awards. Secondly the European Union of Science Journalists’ Associations (EUSJA) who are responsible for representing 2,500 science journalists from 23 national associations in 20 European countries. EUSJA promotes scientific and technical communication between the international scientific community and journalists. This is mainly by organising events, workshops and by working with the European Commission in the interest of Science and Society.

The pre-conference networking event began a towering twenty-three floors above the ground at the highest Champagne bar in Manchester. Here the delegates were introduced to the notion of Manchester as a hub for science with a fly-by video of the ‘science quarter’. This stems from the library at the heart of the city and fans outwards to the south like a segment in an orange. This segment engulfs an impressive two universities, several hospitals and a science park.

Looking towards the south west of the city from "Cloud 23", the bar on the 23rd floor of the Beetham Tower, Manchester, UK. Image credit: David Dixon

Looking towards the south west of the city from “Cloud 23”, the bar on the 23rd floor of the Beetham Tower, Manchester, UK. Image credit: David Dixon

The following morning the conference began at the Manchester Conference Complex in the city-centre focussing on contemporary issues in science journalism and skills for professional development. The panellists and chairs were a mixture of academics and journalists, a range of nationalities and, with experience of the field of science communication. They were allowed to discuss a topic amongst themselves before the conversation was opened to all-comers.

The opening plenary began a discussion on how independent Europe’s science news is and how it can become hijacked by vested interests. For example, if a person writes a scientific story for a newspaper, are they biased by being paid by an external company to write that story? There was a consensus for openness in the funding process behind news stories so that the merits of the story lie in how impartial the writer is perceived to be as well as the content itself.

Although the second session of the day was focussed on the reporting of EU funded science (an 80 billion Euro question) it also gave delegates a chance to mention the elephant in the room – the Brexit. This is the will of a spectrum of people representing the whole political horseshoe for the UK to leave the EU. There was a feeling from the panel that the EU funding structure has allowed science to work on projects that are not just commercially viable in the short-term. The large benefit of cross-country collaboration in Europe was stressed repeatedly. This related to the general acknowledgement that in research the country of origin of specific researchers becomes irrelevant. These thoughts played into the much discussed post-Brexit question(s) – Will it be harder in time for the UK to access EU science funding given its determination to curb net migration and what exemptions (from the UK and EU) can be made for experts in their field? It was also discussed how the UK’s pot of EU science funding may be allowed to be divided up amongst other EU countries in the future. The discussion ended with a series of brief historical anecdotes of governments who favoured local policies/competition which have had a tendency to derail international collaboration. The main point being that research continued but the job was made harder.

The next two sessions focussed on starting a new publication and pitching your idea to an existing publication (sales idea). Using the case-studies of a range of recent start-up publications it was decided that what matters most for creating a publication is: focus, editorial quality, being online, design, collaboration and content.

The closing plenary was concerned with how to work for media that are sceptical about climate change – a place where a science communicator may be forced to go along with the editorial line against their own conviction. A conviction shared by the majority of scientists world-wide who say climate change is happening but argue over the rate that it is occurring. A good recommendation was not to preach but to state facts. The dangers of saying something sceptical as a way into the topic were debated. It was thought that this may backfire if the sceptical comment is later quoted as an expert opinion. At the end of the session the delegates pondered that if the building blocks of climate change were first conceived in 1896 how it is amazing to think that this topic is still controversial 120 years later!

For the final event of the day, the delegates made their way to the Bluedot festival at Jodrell Bank – a festival of music, science, arts, technology, culture, food and film in the shadow of the Lovell Telescope which was illuminated by Brian Eno using large scale projections to create a visual installation. Here the ABSW Science Writers’ Awards was hosted and this blog was short-listed for an award. It provided another great opportunity to network at this thought-provoking conference.

Final

 

How does weather affect volcanoes?

How does weather affect volcanoes?

I was taking a plane trip home recently. To kill the time I got talking with the person sitting next to me and naturally one of their first questions was to ask me what I did for a living. To avoid a complicated discussion about the nuances of my research I summarised – ‘I am a volcanic meteorologist’. They were interested and wanted to know all about how volcanoes affect the weather, my opinion on ‘that Icelandic eruption’ and told me some slightly left-field opinions on climate change. It was an interesting chat and it got me thinking, volcanoes seem to have several well known impacts on weather but can weather have an impact on volcanoes?

At first it appears quite strange that something seemingly so solid can be altered by atmospheric processes. But in the case of mudflows this is exactly what can happen – rain mixing with soil causing soft wet mud to slide down a hill. In the case of volcanoes, a lahar can form, a mudflow consisting of volcanic debris with the consistency of wet concrete which cascades down the slopes of a volcano.

Water has also been known to trigger rockfalls by getting into the cracks between rocks and weakening them. This same erosion process can erode scree from the summit of a volcano.

Lava domes (a roughly circular shaped mound created from the slow extrusion of lava from a volcano) are known to grow in the absence of rainfall. When it rains water seeps into the cracks between rocks in the lava dome. The lava dome is very hot so rain instantly vapourises. Hence a large rain rate is needed to get further inside cracks in the rocks. Once deep inside, the rainwater vapourises into high pressure steam as it encounters temperatures in excess of 300 C. This destabilises the lava dome and sometimes leads to a collapse.

A collapsing lava dome creates a pyroclastic flow, a high-density mix of volcanic rocks and gas travelling down the slopes of a volcano at high speed and destroying almost everything it its path. A 2001 lava dome collapse is thought to have been triggered by rainfall.

Excessive rainfall can and does impact volcanoes. Having said this hurricanes and other large storms, having a rainfall rate needed to cause water to seep into the lava dome of a volcano are mostly found in the tropics.

Do you know of any other cases of weather affecting volcanoes? The author would be interested to know – please post your suggestions in the comments.

Atmospheric Modelling with Meso-NH

Atmospheric Modelling with Meso-NH

Twice a year in Toulouse Meteo-France runs a tutorial on Meso-NH – the non-hydrostatic mesoscale atmospheric model of the French research community. Last week I was fortunate enough to attend their autumn 2015 tutorial. But, what is this model and was the tutorial useful?

Atmospheric models solve the governing equations for atmospheric motions. This allows us, for example, to forecast future atmospheric conditions, to study past climates or even to visualise tiny features over a range of a few tens on metres. Over the last 90 years atmospheric models have developed from a thought concept to low resolution global simulations to high resolution models being able to simulate all kinds of small scale meteorological phenomena. The last of these achievements has been made within the last 15 years using a set of equations and assumptions known as non-hydrostatic modelling.

A non-hydrostatic model is quite simply one in which the atmosphere is not assumed to be in hydrostatic equilibrium. This means that high resolution features can be simulated such as small-scale convection. Processes that are very small or too complex are simulated via parametrisations whereby each small process is represented by relating them to variables at a resolution that the model can resolve. In this way very complex models can be built up simulating many small features of the atmosphere. A mesoscale model has sufficiently high resolution that it can simulate mesoscale weather features.

There are many different non-hydrostatic mesoscale models with different parametrisations for different applications and they are run by different organisations across the world. Recent increases in computing capacity have meant that the complexity of these models is greater than ever before. There are many popular non-hydrostatic mesoscale models including but not limited to the Weather Research and Forecasting Model (WRF), Unified Model (UM), and Meso-NH. This is definitely not the place to start a debate on the drawbacks of different models! However a feature of many but not all of these models is that they are open source, the programming code used to run them is available for modification or enhancement by anyone, this is great for the development of new parametrisations.

The Meso-NH tutorial was split over three days, the first spent on theory about the model. The second was concerned with theory and practise with an idealised atmosphere over fictitious terrain. The third concentrated just on theory and practise with an actual case study of a real meteorological event. Approaching the tutorial in French as a non-native speaker was initially daunting but there are English subtitles and all the documentation is provided in English – this is no excuse not to become fully immersed in this model. Meso-NH is by no means a basic model and the learning curve is steep but coming from a background in a different non-hydrostatic mesoscale model (WRF) it was very intuitive. Impressive features of the model included the breadth of options for the details of different parametrisations and the post-processing display and interpretation options for the model simulations.

What is the biggest air pollution event in the modern era?

What is the biggest air pollution event in the modern era?

It’s hard to think of the scale of the biggest air pollution event in the modern era. Immediately my mind conjures up memories of black and white photographs of the Great London Smog of 1952. Then I start thinking bigger, how about the 1.2 billion vehicles world-wide on the road churning out nitrogen dioxide every single day? Well these are a drop in the ocean compared with bigger industrial polluters. A recent study by the World Health Organisation pegged the financial damage to Europe by anthropogenic air pollution in 2010 at a whopping €2 Trillion. However all of these anthropogenic pollution events pale in comparison compared with mother Earth. A single volcano, Mt. Etna in Sicily has been known to emit the same amount of sulphur in a year as all of French industry.

So, perhaps we just need to find the biggest volcanic eruption in the modern era? This is the 1815 Tambora eruption, the biggest in the last 10,000 years. Actually, no – how explosive a volcanic eruption is and the amount of potentially harmful sulphur dioxide it emits are not always related and even then the dangers these pose to humans depend on weather conditions. In the modern era there is one natural contender: pumping out 15 times more sulphur as the whole European region in 2010, the 1783 volcanic eruption of Laki.

The eruption carried gases into the atmosphere to the start of the tropopause. This is not abnormal, the 2010 eruptions of Eyjafjallajökull followed the same path. What was different from other eruptions was the amount of gas. The Laki eruption carried an estimated 8 million tons of poisonous hydrofluoric acid and 120 million tons of sulphur dioxide into the atmosphere. Here the gases entered the jet stream; a narrow band of intense winds found at about 16 km altitude and this had far-reaching effects.

A high pressure area over Iceland at the time of the eruption caused the poison ridden winds to move south-east and subside over Europe. This resulted in many thousands of deaths because sulphur dioxide gas reacts with moisture in lungs to form sulphurous acid.

High pressure blocking over Iceland (1783)

High pressure blocking over Iceland (top-left) during Laki eruption caused eruption clouds to move over Europe. Image adapted from: Thordarsson and Self (2003).

The ‘Laki haze’ did not dissipate due to hot weather until the autumn and acted like a heat blanket creating convection from increased surface heating resulting in thunderstorms. This directly led to severe flood damage in central Europe. Crop and livestock damage followed. A famine began in Iceland where most of the livestock died from skeletal fluorosis; a condition caused by ingesting fluoride which leads to decreased bone strength, increased risk of fractures and impaired mobility.

This one event weakened the African monsoon circulation leading to less precipitation over the Sahel and resulting in an Egyptian famine due to a shortage of water in the Nile. The Chalisa famine in India occurred also the same year and resulted in 11 million deaths on the subcontinent. However the second of these famines can also be linked to changing El-Niño conditions over the preceding years. The volcanic eruption gases on the atmosphere were as far reaching as North America where there was reported to be ice in the Gulf of Mexico.

A cycle of unusual seasons continued for several years after and caused huge global economic hardship which has been thought to be one of the drivers behind the French Revolution. The large amounts of Sulphur dioxide that remained in the atmosphere may have caused global average temperatures to fall by 1°C for the next couple of years. About 6 million people died as a result of the eruption, either directly or indirectly – this was about 1% of the world’s population at the time.

The Laki 1783 eruption is troubling. In the popular imagination big explosive volcanic events are the most devastating and cone shaped volcanos like Krakatoa are more embedded in our consciousness. However a lesser-known less explosive volcano, if well placed in terms of weather patterns, could potentially be more devastating. If an event like the Laki eruption were to happen again we could expect cold weather and maybe a year without summer. Modern volcanic monitoring practises could help us prepare for such an event but its global nature would still be very disrupting to our lives.

How we might lose the battle against climate change … or against any other environmental problem?

How we might lose the battle against climate change … or against any other environmental problem?

This would not be a blog about atmospheric science if I did not talk about climate change. But I won’t be talking about the science of climate change… there are numerous blogs including here that will talk much better about this. The problem that will be addressed here does not only refer to the “battle” we are currently facing with climate but also numerous other environmental issues (smog, PM2.5 / PM10 pollution, endocrine/ hormone disruptors, pesticides…). For most of these environmental issues, extensive research is already conducted in Atmospheric sciences but these are also tackled in social and economic sciences as well. However, most of the policies in place right now fail to address these issues which are really urgent matter and humans (and other form of life as well) are losing million of hours of life expectancy and hence costing billion of euros to the community.

My point here is that there is a huge gap between what the scientific community understands (and is of course continuing to study) and what is perceive as a threat by the public. More and more scientists engage in outreach programmes and try to convey their findings about their research to the public. One of the other methods scientists use nowadays is more generally known as “open science” where researchers make their data and findings (for ex. with articles) freely available. However it seems that although these practices have been in place for a couple of years / decades, the gap still exists. Either the public has the perception that scientists are totally disconnected from their reality or they do not feel the urgency to take actions to address these issues (because most likely we do not “feel” or “see” the direct impact of the such pollution problems – in the case of climate change we are talking mostly about long term effect on sea level, biodiversity…).

The second issue lies with what kind of policy to put in place based on the findings from the scientific community. Although the aim of science is primarily to understand the “how” and the “why” of questions, it is crucial now for us to take a more firm stand on these issues. Several discussions have already been taking place within the scientific community to decide on whether it is the role of scientist to act as an advocate for a change in policy. For ex. if my research is on climate change and my findings show that human greenhouse gas (GHG) emissions are responsible for the current climate change, is it my role as a researcher to say “loud and clear” that I think we should decrease drastically our GHG emissions? Some scientists think that this is not our role, as we need to be impartial and hence we cannot engage in advocacy. I have to disagree here as we are indeed the most well placed persons to take such stands.

However, I think it is also now crucial for universities and research institutes, to develop new ways (or totally new separate departments) in order to engage with the public and share the knowledge. It is not possible, when the extent of knowledge is so vast, in so many topics, that there are still many areas on which the public / government and the scientific community are in such disagreement. Various situations, in the past, have caused tremendous suffering (for ex. high death and cancer rate in the case of asbestos) and could have been prevented, because the scientific knowledge was here but there was intense lobbying and a lack of political will to change things (it took about 50 years for France to officially ban asbestos after it has been recognized as the origin of pathological diseases).

In view of these situations, policy change will definitely come when the public “knows” and can hence ask for a change with their local / national / international governments. This bottom-up approach seems to be the most likely way with which we will be able to address these environmental issues in the future. The problem here is that we (scientists in general) have to ask ourselves why is it that our research influence so marginally policies that are put in place. Are we not engaging with the public enough? Should we share our results/findings differently? Are international organisations the best way to find consensus on such topics? I agree that scientists cannot solve all the problems of the world but the research community is one of the pillars of the society and should engage as such in the debates the society is facing. Although I started with a very bleak perspective (and for now this seems to be the case with many challenges we are facing) there is still some hope for the future. We will see, for ex., in the COP21 international meeting if an agreement will be reached on the climate change topic… but I have serious doubts about this being the case.

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