Doubt cast on global firestorm generated by dino-killing asteroid

Pioneering new research published in the Journal of the Geological Society.has debunked the theory that the asteroid that is thought to have led to the extinction of dinosaurs also caused vast global firestorms that ravaged planet Earth.

A team of researchers from the University of Exeter, Imperial College London, Planetary Science Institute and University of Vienna recreated the immense energy released from an extra-terrestrial collision with Earth that occurred around the time that dinosaurs became extinct. They found that the intense but short-lived heat near the impact site could not have ignited live plants, challenging the idea that the impact led to global firestorms.

These firestorms have previously been considered a major contender in the puzzle to find out what caused the mass extinction of life on Earth 65 million years ago.
The researchers found that close to the impact site, a 200 km wide crater in Mexico, the heat pulse - that would have lasted for less than a minute - was too short to ignite live plant material. However they discovered that the effects of the impact would have been felt as far away as New Zealand where the heat would have been less intense but longer lasting - heating the ground for about seven minutes - long enough to ignite live plant matter.

The experiments were carried out in the laboratory and showed that dry plant matter could ignite, but live plants including green pine branches, typically do not.

Dr Claire Belcher from the University of Exeter said: “By combining computer simulations of the impact with methods from engineering we have been able to recreate the enormous heat of the impact in the laboratory. This has shown us that the heat was more likely to severely affect ecosystems a long distance away, such that forests in New Zealand would have had more chance of suffering major wildfires than forests in North America that were close to the impact.  This flips our understanding of the effects of the impact on its head and means that palaeontologists may need to look for new clues from fossils found a long way from the impact to better understand the mass extinction event.”
Plants and animals are generally resistant to localised fire events - animals can hide or hibernate and plants can re-colonise from other areas, implying that wildfires are unlikely to be directly capable of leading to the extinctions. If however some animal communities, particularly large animals, were unable to shelter from the heat, they may have suffered serious losses. It is unclear whether these would have been sufficient to lead to the extinction of species.

Dr Rory Hadden, who was part of Dr Guillermo Rein's group in Imperial College by the time of the research and now is at the University of Edinburgh, said: “This is a truly exciting piece of inter-disciplinary research. By working together engineers and geoscientists have tackled a complex, long-standing problem in a novel way. This has allowed a step forward in the debate surrounding the end Cretaceous impact and will help geoscientists interpret the fossil record and evaluate potential future impacts. In addition, the methods we developed in the laboratory for this research have driven new developments in our current understanding of how materials behave in fires particularly at the wildland-urban-interface, meaning that we have been able to answer questions relating to both ancient mass extinctions at the same time as developing understanding of the impact of wildfires in urban areas today.”


The research was supported by a European Research Council Starter Grant, a Marie Curie Career Integration Grant, the Leverhulme Trust, the EPSRC and the Austrian Science Fund

Research Associate position on fire protection engineering in Imperial College London

Research Associate in the Thermofluids Division at the Department of Mechanical Engineering, Imperial College London.

Maximum salary on appointment will be £33,410 per annum*

*Candidates who have not yet been officially awarded their PhD will be appointed as Research Assistants within the salary range £29,350 - £32,520 per annum.

Fixed-term appointment available for up to 8 months in the first instance.

The Thermofluids Division wishes to appoint a Research Associate to conduct research into systemic fire protection engineering at Imperial College London.

The Hazelab is the multidisciplinary research group led by Dr Guillermo Rein and part of the Thermofluids Division in the Department of Mechanical Engineering. The purpose of the group is to reduce the worldwide burden of accidental fires and protect people, their property, and the environment. To do so, Hazelab studies computationally and experimentally heat transfer processes, condensed-phase chemistry and thermodynamics of reactive solids.

The Research Associate under the supervision of Dr Rein, will be involved in the project N-LAYERS to conduct a study and write a white paper where a holistic view of fire protection engineering is created and the role of prevention is examined. Fire safety is made of a series of layers (e.g., prevention, fuel control, passive and active systems, evacuation, and structural response). All layers have a role in fire safety, but not all layers are equally important, effective or costly. In this context, N-LAYERS wants study in-depth the role of prevention in a systemic view of fire protection.

The Associate would be in charge of conducting the multidisciplinary literature review on systemic thinking, resilience and layers of fire protection; construction of a novel framework for the white paper based systemic thinking; communicate with collaborators; and write the white paper.

A PhD (or equivalent experience and/or qualifications) or near completion of a PhD* in an area pertinent to the research subject e.g. Fire Protection Engineering, Mechanical Engineering or Chemical Engineering is essential.  In addition some background in fire dynamics and risk is also essential. High quality writing in technical English is desirable.

Informal e-mail enquiries may be made to Dr Guillermo Rein at g.rein@imperial.ac.uk or +44(0) 20 7594 7036.

Committed to equality and valuing diversity.  We are also an Athena SWAN Silver Award winner, a Stonewall Diversity Champion, a Two Ticks Employer and are working in partnership with GIRES to promote respect for trans people.

                               

Closing Date:  20 February 2015 (midnight GMT)

                               

How To Apply:                  

Our preferred method of application is online via our website.  Visit at http://tinyurl.com/hazelab or go to http://www3.imperial.ac.uk/employment (Select “Job Search” then enter the job title or vacancy reference number into “Keywords”). Please complete and upload an application form as directed quoting reference number EN201500023SF, you must submit an application form for our posts along with a CV, if you do not fill in an application form, you will not be considered.

Alternatively, if you are unable to apply online, please email Ms Claire Soulal, Academic Administrator at: c.soulal@imperial.ac.uk to request an application form.

Peat fires - a legacy of carbon up in smoke

Press Release:

It reads like a movie script – ash falling from the sky, thick smoke shutting down airports and businesses, road closures trapping remote northern villages. But this is not from a script; rather, it is a new study of what could happen through peat burning.

In an international paper released in the January edition of the journal Nature Geoscience, the researchers, led by University of Guelph professor Merritt Turetsky, focus on fires that burn through thick layers of peat (dead plant debris) that blanket the ground in ecosystems ranging from the tropics to the arctic.

Peat is a legacy of plant activity – plants acquiring carbon from the atmosphere to build their biomass. Those plants die and are incorporated into the soil. When those soils are too wet to support high levels of decomposition, those plant remains pile up over time.

"When people picture a forest fire, they probably think of flames licking up into tree tops, and animals trying to escape," said Turetsky. "But peat fires tend to be creeping ground fires. They can burn for days and weeks, even under relatively wet conditions. They lack the drama of flames, but they produce a lot of smoke." That smoke makes peat fires dangerous to human health. It can worsen air quality and even trigger asthma and other respiratory problems. "We know fires serve as a major source of human mortality globally," said Turetsky. "We are starting to understand that peat fires cause some of the most extreme air quality issues, but in general they are poorly understood." Turetsky and Brian Benscoter teamed up with fire scientists to summarize what is known about peat fires, from massive lightning-ignited fires that burn large areas of the boreal region to tropical fires often triggered by human activity.

"The tropical peatlands in Southeast Asia are a clear demonstration of how human activity can alter the natural relationships between ecosystems and fire," said Susan Page, a University of Leicester professor and co-author on this study. "Tropical peatlands are highly resistant to natural fires, but in recent decades, humans have drained peatlands for plantation agriculture. People cause the deep layers of peat to dry out, and also greatly increase the number of fire ignitions. It's a double threat." This causes a host of problems, including health issues, airport and school closures, and political tensions. The paper concludes that almost all peat-rich regions will become more susceptible to drying and burning with a changing climate.

“Thanks to satellite data, we are fully aware of the vast scale of burning in drained peatlands, mostly in Indonesia,” said co-author Guido van der Werf, a professor at Amsterdam’s VU University and and co-author on this study. “The scary thing is future climate change may actually do the same thing: dry out peatlands. If peatlands become more vulnerable to fire worldwide, this will exacerbate climate change in an unending loop." Peatlands store a large amount of carbon due to thousands of years of plant activity. When peat burns, carbon is released into the atmosphere.

 “Smouldering peat fires already are the largest fires on Earth in terms of their carbon footprint,” said Dr Guillermo Rein from Imperial College London, and and co-author on this study.

Peat fires and their effects will only increase as more towns are built and more resources developed near peat-rich regions, said Turetsky. “These types of fires have different impacts on ecosystems, and traditional fire management techniques will not be effective in combating peat fires. We need new tools to deal with these issues,” she said. The study is titled “Global vulnerability of peatlands to fire and carbon loss.”

Contacts: Guillermo Rein, Imperial College g.rein at imperial.ac.uk