What emission profiles aid remaining below two degrees of global warming?

In recent days multiple marches have taken place around the world, timed to coincide with the UN Climate Change summit in New York (23 September 2014). The many protestors have urged more action by governments to reduce greenhouse gas emissions.

CEH climate modeller Dr Chris Huntingford commented:

“There is still significant debate as to what constitutes safe levels of global warming. This almost certainly depends on the different impacts which can result from varying levels of warming. For example, meteorological changes affecting crop productivity detrimentally could be produced by a different level of climate change to that causing unwelcome sea-level rise. Yet despite this, the 2009 climate conference in Copenhagen pushed for the single threshold of no more than two degrees of global warming. There is a persuasive argument that this was a major achievement, as a single easy to understand temperature threshold will probably gain more traction in policymaker circles than debating a range of possible climatic futures.

The immediate question then became: “What emissions profiles can keep us below two degrees of global warming?” Working with colleagues from Met Office Hadley Centre, University of Oxford, Manchester Metropolitan University and the Committee on Climate Change, we carried out a study using a relatively simple coupled climate-carbon cycle model, but one capturing uncertainty based on differences between the fully complex climate models, as operated by various research centres across the world. The resultant paper provided “look-up” diagrams, where different emissions levels of years 2020 and 2050 can be related to the probability of remaining below two degrees. The paper also linked these 2020 and 2050 levels to both year of maximum emissions and required year-on-year emission cuts for the decades thereafter, in order to fulfil them.

The paper was published in 2012 in the journal Environmental Research Letters, but its message still stands. Namely that to have a reasonable chance of constraining warming to two degrees then emissions need to peak in the next few years, followed by year-on-year cuts of at least 3%.”

Chris Huntingford

UN Secretary General Ban Ki-Moon (front row, second from right) at the People's Climate
March in New York, held ahead of the Climate Summit he hosted at UN headquarters in
September 2014. Photo: UN / Mark Garten

Additional information

The paper can be read on the Environmental Research Letters website. It is "open access" allowing circulation of the document, and can be found here (doi: 10.1088/1748-9326/7/1/014039).

Chris Huntingford is a climate researcher at the UK Centre for Ecology & Hydrology, and also long-term visiting scientist at the Oxford University Centre for the Environment.

Information on the UN Climate Summit 2014

CEH science at EGU2014

The breadth of CEH science has been well represented in several sessions at this week’s European Geosciences Union General Assembly 2014 in Vienna. The event brought together more than 11,000 scientists from all over the world into one meeting covering all disciplines of the Earth, planetary and space sciences. Check out our Storify for a flavour of what’s been going on for CEH or scroll down for abstracts of our lead talks and posters.

Abstracts

Stephen Thackeray presented an update on the Shifting Seasons and climate change phenology project which he leads. For more details of the project, visit the webpage.

Andrew Chiverton: Which catchment characteristics control the temporal dependence structure of daily river flows?

Kelly Mason: Regulation of Boreal soil respiration - evidence from a Swedish forest fire chronosequence

Ed Rowe: Towards an understanding of feedbacks between plant productivity, acidity and dissolved organic matter

James Miller: Assessing the relative and cumulative impacts of future urbanisation and climate change on storm runoff in a peri-urban catchment

Steven Cole: Probabilistic flood forecasting for Rapid Response Catchments using a countrywide distributed hydrological mode

Kerry Dinsmore: Aquatic carbon and GHG losses via the aquatic pathway in an Arctic catchment

Cecilia Svensson: Improving winter river flow forecasts for the UK

Andy Robertson: Land use change to Miscanthus - measured and modelled changes in soil carbon fractions

Carole Helfter: Effects of winter temperature and summer drought on net ecosystem exchange of CO2 in a temperate peatland

Andy Robertson: Using an input manipulation experiment to partition greenhouse gas fluxes from a commercial Miscanthus plantation in the UK

Cecilia Svensson: Seasonal UK river flow forecasts based on persistence and historical analogy

Jessica Adams: Estimating sources and fluxes of dissolved and particulate organic matter in UK rivers

Kerry Dinsmore: Multisite comparison of drivers of methane emissions from wetlands in the European Arctic - influence of vegetation community and water table

Garry Hayman: Wetland methane modelling over the Scandinavian Arctic - performance of current land-surface models

Additionally, our scientists have been busy collaborating with many international colleagues who also gave talks at the event: topics included the Globolakes project, atmospheric ammonia, emissions modelling at the field scale, monitoring changes in peatland, greenhouse gas production from shallow lakes and ponds, soil organic carbon dynamics, vulnerability of ecosystems to extreme climatic events, water quality sampling, streamwater nitrate dynamics, soil status in drought, crowd-sourcing data with the mySoil app, historical flood information, using isotopes in Arctic catchments, the sensitivity of river reaches to water abstraction, soil hydraulics, peatland modelling, microbial carbon turnover and hazard assessment for volcanic eruptions.

Kelly Mason, Research Associate in Plant-Soil Interactions at CEH, presented
work on regulation of boreal soil respiration, which was carried out with
colleagues from CEH, Lancaster University, University of Washington and Bangor
University. Photo: Andy Robertson

Posted by Paulette Burns

CEH research shows ammonia emissions affect sensitive habitats upwind of a poultry farm

CEH recently led a study that found that ammonia emissions from an intensive poultry unit were detected nearly three kilometres upwind, deep within a Natura 2000 site, Newborough Warren, an important sand dune system in Wales. The research was highlighted by the European news alert service Science for Environment Policy, as well as industry website The Poultry Site.

The paper by Dr Laurence Jones describes the findings, which have major implications for the way we consider the control of emissions from intensive animal production units.

Laurence continues:

“While the majority of ammonia is transported downwind, this study suggests that ammonia emissions could be a significant source of nitrogen pollution to sensitive sites even upwind from the source.

Mobile sand dunes, a highly biodiverse habitat

Ammonia caused exceedance of UNECE nitrogen thresholds within the nearby Natura site and experiments showed that dune plant species were being affected by the nitrogen. The paper has already convinced the Environment Agency to consider effects of local wind direction and more recent meteorological data in casework.

Ammonia emissions were monitored around the farm and up to 2.8 km upwind of the prevailing wind direction for a year.

At the furthest sampling point upwind, levels of ammonia concentrations rose and fell in cycles coinciding with emissions from the farm in all months, although were much lower (averaging 0.9 μg/m³, compared with 60.1 μg/m,³ at the farm itself).

The Natura site, Newborough Warren, is one of Wales’ largest sand dune systems and is designated for a wide range of Biodiversity Action Plan priority habitats and rare species. Within parts of the site, ammonia from the farm caused exceedance of the critical level for ammonia of 1 μg/m³, and exceedance of the critical load of 8 – 15 kg N/ha/yr for sand dune grasslands. The farm contributed an additional 50% to the background levels of nitrogen deposition in parts of the site.

Common Centaury, Centaurium erythraea, a low growing biennial
often found on sand dunes

Experiments in the study showed that plants take up the ammonia as a nutrient source, and nitrogen-loving grasses and other species grew better when exposed to the ammonia than other dune species.

The study was funded by Countryside Council for Wales (now Natural Resources Wales). It confirms other CEH studies which highlight that sand dune habitats are sensitive to excess nitrogen pollution from atmospheric deposition and in groundwater.”

Laurence Jones

Additional information

Paper reference: Jones, L., Nizam, M.S., Reynolds, B. et al. (2013). Upwind impacts of ammonia from an intensive poultry unit. Environmental Pollution. 180: 221-228. DOI: 10.1016/j.envpol.2013.05.012

Related CEH links

Staff page of Dr Laurence Jones 

British birds, pollinators and penguin poo - paperblog 7

In the latest edition of the CEH paperblog, we first highlight a recent PLoS ONE paper that involved researchers from Anglia Ruskin University and Dr Shelley Hinsley of CEH in a ten-year study of British birds, and how weather interacts with habitat to determine breeding success. The Cambridgeshire-focused study discovered that birds breeding in urban areas are better able to cope during unusually cold and wet weather, because they are less reliant on a single food source for feeding their chicks. The study compared 2012 - with its notable weather, including a cold and wet spring and lower than average temperatures - to the previous nine years.

Over the whole ten years of the study, birds living in the traditional woodland habitat had fared significantly better and produced larger and healthier broods than their city cousins. However, if extreme weather events become more commonplace due to the effects of climate change, then those birds living in urban environments may ultimately have the advantage. The PLoS ONE paper is open access.

Staying with PLoS ONE, and open access, a study led by Professor Hui Wang of CEH has used new technology to investigate viruses such as varroa destructor virus in honeybees and bumblebees. The results, from a small field trial, show how the use of Next Generation Sequencing (NGS) technology can help understand virus infections in key pollinating insects, with novel observations even from a small sample size. Such technology has potentially interesting applications in ecological and environmental science.

A new paper in the Journal of Applied Ecology also looks at pollinators and other invertebrates that provide important ecosystem services crucial to crop production. A team of researchers led by CEH mapped the distribution of species richness and functional diversity for ground beetles which are important in the delivery of natural pest control and for bees, important for pollination. Understanding national patterns can help to promote more effective crop management and contribute to longer-term food security.

Next, penguins are under the spotlight in a new paper in Atmospheric Environment. The emissions from remote seabird colonies often represent the main source of atmospheric nitrogen into surrounding ecosystems, and can provide useful case studies for scientists investigating nitrogen cycling and emission processes. However before this study no field-based estimates of ammonia emissions from penguin colonies had been published. Data was collected from seven locations around an Adelie penguin colony in the Antarctic and three different atmospheric dispersion models were used to derive the first field-based emission estimates of a penguin colony.  The researchers, including Sim Tang and Mark Sutton of CEH, estimate that 2% of the nitrogen excreted by the penguins is emitted as ammonia.

Finally, a featured article in the Journal of Environmental Quality led by Prof Andrew Sharpley (University of Arkansas) and involving Helen Jarvie, Bryan Spears and Linda May of CEH, used long-term monitoring data from a range of case studies (including CEH's Loch Leven and River Lambourn sites) to demonstrate the timelines and processes associated with recovery of water quality following phosphorus reduction measures. The team reported recovery times ranging from years to centuries across terrestrial and aquatic ecosystems. Read more in the open access paper and more background in a CEH news story.

Paulette Burns, Media Coordinator

Additional information

If you'd like a fuller picture of new papers from CEH, just follow the CEH Paper Alerts Twitter feed, which lists CEH peer-reviewed papers newly published online. Full details of Centre for Ecology & Hydrology science publications, including those published in peer-reviewed science journals, are eventually catalogued on the NERC Open Research Archive (NORA).

Those of you who follow the scientific literature will know some journal websites require registration and some are subscription-only. CEH, as part of NERC, is working with publishers and funders to make more of our output open access, and we have indicated above where this is the case.

We also publish lots of our other outputs including biological records atlases and project reports. More details can be found in the publications section of the CEH website.

Monitoring mercury in the atmosphere

Edinburgh is the venue for the International Conference on Mercury as a Global Pollutant later this month (28 Jul - 2 Aug 2013), and CEH's John Kentisbeer will be among the scientists presenting at the event. Here John tells us a bit more about mercury and also why and how CEH monitors its presence in the atmosphere.

Why does the Centre for Ecology & Hydrology monitor mercury in the atmosphere? Put simply, because it is a poisonous pollutant that needs to be better understood and controlled.

Mercury is a special metal because it is a liquid at ambient temperature and pressure, leading to its nickname of quicksilver. This liquid mercury easily turns to vapour and can exist in the atmosphere for up to a year. It can enter the atmosphere through natural processes, such as volcanic eruptions, but humans add to this by making chemicals, burning coal, disposing of mercury-containing waste, as well as gold mining and many other processes. Have you ever heard of the phrase "Mad as a hatter"? It comes from using mercury in the manufacturing of felt hats in the 19th century. Nowadays, mercury is used in all manner of fluorescent light bulbs and you may even have some in your mouth if you have a filling!

Mapping mercury concentrations in air over Europe

Of course there has always been mercury in the atmosphere, but not as much as there is now. Gold rushes since the 16th century and processes linked to the industrial revolution are among ways that humans dramatically increased the amount of mercury in the atmosphere, leading to a peak in the 1980s before control measures were introduced, curbing emissions and allowing levels in the atmosphere to fall. They have been pretty constant since the mid-1990s.

The reason we should all care about mercury in the atmosphere is that it is one part of the global mercury cycle. It doesn't just stay in the atmosphere; it can be deposited to land and water directly, and in rain. This allows it to accumulate in the environment where it can have a detrimental effect by being transformed into a more reactive form, such as methylmercury. Methylmercury is highly toxic and is easily absorbed in the bodies of animals and humans. If methylmercury enters a lake, it will be absorbed by small fish through their diet, and when the small fish are eaten by bigger fish the methylmercury moves to the bigger fish; this carries on right up the food web, until you get to humans, a process called bioaccumulation. This can result in significant mercury exposure in humans and lead to Minimata disease, which can cause serious neurological damage, insanity, paralysis and, in extreme cases, death. It affects animals too - in one outbreak in Japan it was called "dancing cat fever" because of the effects on cats. For this reason, many countries advise their citizens how much of certain fish, such as tuna, they should eat.

UK monitoring

CEH monitors mercury at eleven sites across the UK to assess the rural background levels. We monitor both the mercury in the atmosphere, as well as mercury in rainfall. Mercury can be present in the atmosphere in three forms: it can be a gas, it can be part of a molecule or it can be stuck to particles. Mercury gas can be present in the atmosphere for up to a year, while mercury as a compound or stuck to a particle has a much shorter lifetime and is easily removed by rain. Gaseous mercury can be changed in the atmosphere to the other two types, but this is generally thought to be quite a slow process. Our monitoring, undertaken on behalf of the UK governments, forms part of a European and global programme for monitoring mercury in the atmosphere to help understand local, regional and global trends.

CEH's atmospheric monitoring site at Auchencorth Moss in Scotland

In order to work out how much mercury is in the air, we have to capture it, which we do using gold. We pass air across a gold surface, to which the mercury sticks as it forms an amalgam. Once we have finished sampling a known volume of air, we heat the gold up and the mercury is released from the surface and is sent to the analyser, which uses ultraviolet light to calculate the mass of mercury in the sample. We can then work out the original concentration in air.

Typically background concentrations of gaseous mercury in the northern hemisphere are about 1.4 - 1.7 nanograms per cubic metre of air. That is 0.0000000014 grams, which seems really small, but these small amounts can accumulate to cause potentially harmful effects. We monitor mercury in air every five minutes at two sites, one at Auchencorth Moss in Midlothian, Scotland and the other at Harwell in Oxfordshire, England. At the other sites, we have low volume samplers which sample Total Gaseous Mercury (TGM), comprising gaseous elemental mercury and mercury-containing compounds, for two-week periods.

A low-volume Total Gaseous Mercury sampler

Our data show that average concentrations of mercury in the south-east of the UK are higher than in the north-west. This would be consistent with the urbanisation of the UK, but also with air containing mercury coming from the European mainland. Using the five-minute data and local wind speed and direction, we can even start to pinpoint possible local emission sources, such as coal-fired power stations or crematoria.

By understanding the sources and their influence on atmospheric mercury, we provide evidence to policy makers to help them make informed decisions on the problems we face. When control measures designed to reduce emissions are introduced, we can then monitor the impact and their effectiveness.

CEH also measures mercury content in soils as part of the UK Countryside Survey, which allows us to better understand how mercury enters and leaves soils, and its impact on the soil environment. Additionally, CEH scientists at Bangor also coordinate the ICP Vegetation programme (the International Cooperative Programme on Effects of Air Pollution on Natural Vegetation and Crops) which surveys the concentration of heavy metals, including mercury, in mosses across Europe.

We also operate the Predatory Bird Monitoring Scheme, which examines the concentrations of pollutants in certain dead birds as a way of identifying risks to wildlife and potentially humans. Mercury is one of the chemicals monitored as part of this programme as it is thought to be a contributing factor to the decline of some bird species.

• Find out more about CEH's various monitoring activities with the links below. And if you are in the Edinburgh area, the International Conference on Mercury also has a public open day. Come along to the Lomond Suite, Edinburgh International Conference Centre, 150 Morrison Street, on Sunday 28 July between 2pm-4.30pm.

John Kentisbeer

Additional information

UK Pollutant Deposition: Heavy Metal Monitoring

UK Countryside Survey

Predatory Bird Monitoring Scheme

ICP Vegetation

2013 International Conference on Mercury as a Global Pollutant website 

Staff page of John Kentisbeer at CEH

2 degrees, global warming and a planet under pressure?

The Planet Under Pressure conference has been taking place in London this week (26-29 March 2012), a major international gathering of policymakers, business leaders and scientists focusing on the challenges of global sustainability. On Monday delegates listened to a series of presentations on climate science and uncertainty. Coincidentally on the same day one of CEH’s climate scientists, Dr Chris Huntingford, had a new paper published in the journal Environmental Research Letters entitled “The link between a global 2°C warming threshold and emissions in years 2020, 2050 and beyond”.

The paper gives details of a recent study that investigates the link between the chances of global warming remaining below two degrees through to year 2500, and what this implies for emissions in 2020 and 2050. 2020 and 2050 are two ‘target’ years of particular relevance to policymakers, including many of those attending the Rio summit later this year.

You can hear Chris talk more about his climate modelling work in a video on our YouTube channel:

Additional information

• Environmental Research Letters
• Dr Chris Huntingford
• CEH’s YouTube channel
• Planet under Pressure conference