BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Talks.cam//talks.cam.ac.uk// X-WR-CALNAME:Talks.cam BEGIN:VEVENT SUMMARY:Methane in the Earth System Symposium - John Burrows\, Nic Gedney\ , Euan Nisbet\, Matt Rigby\, Philip Sargent DTSTART:20140605T130000Z DTEND:20140605T170000Z UID:TALK51934@talks.cam.ac.uk CONTACT:Dr Michelle Cain DESCRIPTION:CCfCS symposium on the topic of methane in the Earth system. A map of the venue can be found "here\,":http://map.cam.ac.uk/Centre+for+Ma thematical+Sciences and further travel information "here.":http://www.cms. cam.ac.uk/visiting/\n\nOpen to all.\n\nConfirmed speakers are: \nProf John Burrows (University of Bremen)\, \nDr Nicola Gedney (UK Met Office)\, \nP rof Euan G Nisbet (Royal Holloway University of London)\, \nDr Matthew Rig by (University of Bristol)\, \nDr Philip Sargent (DECC).\n\nThis meeting i s supported by MethaneNet. If you are a UK-based early career researcher o r student and wish to attend from outside Cambridge\, please contact miche lle.cain@atm.ch.cam.ac.uk for details of travel funds from MethaneNet.\n\n |1400 |Prof Euan G. Nisbet |Is methane the canary in the mine?|\n|1430 |D r Nicola Gedney |Modelling large-scale wetland methane emissions|\n|1500 | Tea/coffee break||\n|1530 |Prof John P. Burrows |Observing the Anthropocen e from Space: Methane|\n|1600 |Dr Matt Rigby |Recent trends in atmospheric methane: what can we learn from data and models?|\n|1630 |Dr Philip Sarge nt |A DECC perspective on methane|\n|1700-1830 |Poster and networking sess ion with refreshments| | \n\n*Abstracts:*\n\n*Is methane the canary in the mine?*\n\n*_Prof Euan G. Nisbet_*\n\nUntil 1986\, British coal miners too k canaries underground. When the canary expired\, that meant there was let hal CO in the air and probably methane also: the canary's death implied an explosion was on its way. Curiously\, atmospheric methane is in some ways the canary of climate change. It is a "first responder" to change: many f eedback loops drive methane emissions when climate warms or cools\, and me thane is thus an early indicator of change. Because there is broadly an A rrhenius relationship between temperature and methane production\, a warme r biosphere is generally a more methane-productive biosphere. Not only tha t\, but rainfall under the convergence zones intensifies\, leading to more wetland and also also more grass and tree growth\, providing fuel for dry season biomass burns. Over decades to centuries of climate warming\, met hane hydrates decay\, and thermokarst develops in permafrost yedoma: more methane is given off\, though much of this is rapidly oxidised by methanot rophs. \n\nThe late glacial record shows these responses sharply\, and is very instructive\, though not yet fuly explained. Further back in time\, the Palaeocene-Eocene Thermal maximum (about 56 Ma ago) similarly may reco rd very sharp changes in methane emission. At the present-day\, the post-2 000 record may be showing fluctuating natural responses to climate events. Until 2007\, methane growth was limited despite rapid human economic gro wth and increasing use of coal and gas. Possibly in part this stability in atmospheric methane reflected relatively dry conditions in key tropical a nd boreal areas. After 2007\, climate shifts may have led to stronger inte rtropical convergence: and thus increased methane production. Over the pas t few years methane C isotopes have been shifting 'light'\, implying propo rtionately stronger biological sources despite continuing growth in energy use in East and South Asia. \n\n*Observing the Anthropocene from Space: M ethane*\n\n*_Prof John P. Burrows_*\n\nThe industrial revolution\, which b egan in the UK in the late 18th century\, has been fuelled by the use of c heap energy from fossil fuel combustion. It has facilitated a dramatic ris e in both the human population\, now above 7 Billion with 50% now living i n urban agglomerations\, and its standard of living. It is anticipated tha t by 2050 there will be of the order of 8.3 to 10 billion people\, 75% liv ing in cities. Anthropogenic activity has resulted in pollution from the l ocal to the global scale changes in land use\, the destruction of stratosp heric ozone\, the modification of biogeochemical cycling\, acid deposition \, impacted on ecosystems and ecosystem services\, destruction of biodiver sity and climate change. The impact of man has moved the earth from the Ho locene to the new geological epoch of the Anthropocene. To improve our und erstanding of the earth atmosphere system and the accuracy of the predicti on of its future changes\, knowledge of the amounts and distributions of t race atmospheric constituents are essential -“One cannot manage what is not measured”. An integrated observing system\, comprising ground and sp ace based segments is required to improve our science and to provide an ev idence base needed for environmental policymakers. \n\nPassive remote sens ing measurements of the up-welling radiation at the top of the atmosphere from instrumentation on space borne platforms provide a unique opportunity to retrieve globally atmospheric composition. This presentation describes the approach and the results obtained from the SCIAMACHY (SCanning Imagin g Absorption spectroMeter for Atmospheric CHartographY) which flew on the ESA Envisat 2002 to 2012. SCIAMACHY was the first instrument to use NIR an d SWIR measurements to retrieve the dry mole fraction of carbon dioxide an d methane from space. Its measurements yield sufficient accuracy to determ ine and constrain surface fluxes at the regional scale. The GOSAT Tanso in strument and its results will also be discussed as well as the objectives of the active mission MERLIN\, a demonstrator LIDAR mission. The potential successors of SCIAMACHY\, having capability to measure CH4 such Sentinel 5 Precursor\, Sentinel 5\, CarbonSat\, and SCIA-ISS will also be addressed .\n\n\n*Recent trends in atmospheric methane: what can we learn from data and models?* \n\n*_Dr Matt Rigby_*\n\nLong-term measurements of atmospheri c methane reveal intriguing inter-annual fluctuations. These changes could be linked to perturbations in the complex mix of sources\, or in the stre ngth of atmospheric and terrestrial sinks. Atmospheric observations of met hane and other species can be used to provide constraints. For example\, r ecent measurements from the Advanced Global Atmospheric Gases Experiment ( AGAGE) show that an upturn in global methane levels\, beginning in 2007\, is likely due to an increase in emissions\, because the lifetimes of subst ances that also react with methane’s principal sink\, the hydroxyl radic al\, do not appear to exhibit significant changes. I will examine our curr ent ability to determine methane sources using atmospheric measurements at both global and regional scales\, with a particular focus on new UK emiss ions quantification efforts being carried out by the Deriving Emissions re lated to Climate Change (DECC) network. I propose that our existing method s for quantify uncertainties in “inverse” modelling frameworks are lik ely to be inaccurate\, and that new approaches are needed if our estimates are to be relevant for emissions verification purposes. I will introduce a hierarchical Bayesian framework for accounting for some unknown uncertai nties in inverse frameworks\, and discuss the remaining problem of quantif ying the influence of transport model biases.\n\n*A DECC perspective on me thane* \n\n*_Dr Philip Sargent_*\n\nOur concern in the Science and Innovat ion team in DECC is ensure that methane emissions are properly taken into account in the various policies and negotiations that other parts of DECC participate in\, but also that money spent on methane reduction does not s eriously reduce funds available for CO2 reduction as CO2 is the long-term problem. A single\, simple trade-off number - such as the GWP(100y) - is w hat we use but it can’t do all that we might want. We also have to be aw are that government policy is to encourage “genuine carbon emission redu ctions” but precisely how that phrase should be interpreted depends on t he timescale under consideration\, which may be deliberately unelucidated for any one policy. Sometimes stronger enforcement of low methane emission s could actually reduce spending\, thus enabling more to be spent on CO2 r eductions\, so we are particularly keen to identify those options.\n\nWhat we particularly need from the research community is a wider and more cons idered range of options for the trade-off between methane and CO2. What is the most appropriate period of years to use for the GWP multiplier? 100y ? 20y? Or the integral up to a specific date (such as 2050) rather than an integral over a fixed period of years? If it is to a fixed date\, should that be the date at which we expect global average temperatures to peak\, or the date at which regional average temperatures for the most vulnerable populations/biomes will peak? Or some internationally-agreed target date? Or should we be more interested in an integrated “date” representing the duration during which global temperatures are expected to be above 2 ⁰C ? We realise that properly answering these questions requires economi sts as well as climate scientists. We also realise that these questions pa rticularly apply to methane as the time-constant of 12.4y means that these different metrics produce very different results for methane but not for other GHGs.\n\nIPCC AR5 says that GWP(100y) is 28x (+/- 30% at 2 sigma) an d that it should be 34x if hydroxyl feedback is included. What would be th e appropriate confidence range for that hydroxyl feedback number though? A nd how does it vary if we are interested in 50y instead of 100y ? How appr opriate is the 34x value for national policy assessment? LOCATION:Centre for Mathematical Sciences\, meeting room MR2 END:VEVENT END:VCALENDAR