 My name is Richard Baker, I have the honour of being the Pro Vice-Chancellor of Student Experience at ANU. It's my duty just to welcome you here tonight and do what ANU always does and acknowledge the traditional owners of the country we're on. As many of you heard me say before, there's something quite special about October. So for about 25,000 years at least, people have been coming here together for interview ceremonies, sharing information. So the Nettagambri, Ngunnawal people, this area were joined by Yorah people from what we now call the Sydney area, UM people from the South Coast, Radri people from out west and they're coming here to feast on bogon moths, the moths that probably annoy you at night around the lights. And after three or four weeks of eating bogon moths, apparently it was the equivalent of eating large jars of peanut butter, so people's skins were glistening. But also they were full from lots of ceremonies and lots of exchange of exciting ideas and I think it's a nice tradition ANU is continuing and as we'll hear I'm sure from the students it's like many of ANU's traditions, something that students have started, maintained and continued. It's also my great pleasure to be here tonight with Jeanette speaking. Jeanette and I started at ANU the same week in 1993 in the same department and she came all the way from South Africa. I came all the way from the National Museum but we've worked together very closely ever since and I've had the great pleasure of having seen her lecture many times. I'm sure we're going to have something special tonight. So we've no further ado, I'll hand over to Paula. Is that right? Paula knew it, the Dean of Students. So welcome from me too. We've met here on the final Thursday of the teaching year every year since 2006 so we've got a wonderful ANU ritual, a ritual of celebration, of thanks, of achievement, acknowledged and of relieved gratitude as we realised that we've all survived or nearly survived another academic year. The last lecture event commenced at ANU in 2006 as an event to mark the end of the academic year. It arose as an initiative of ANUSA and PASA, the undergraduate and postgraduate student associations and through their presidents seeking a new kind of teaching award, an award and a celebration designed and driven by students. It was modelled on an event that the 2006 PASA president witnessed at the University of Utah. It was a last lecture to mark the end of the academic year with the lecturer chosen by students in a campus-wide vote. The PASA president at that time observed the occasion as an important ceremonial event that brought the whole university community together. So here we are in 2015 celebrating the ninth ANU last lecture. I've attended almost all the last lectures, certainly all the ones that I was here to be able to attend and I'm sure I'm not alone in that. It is a warmly anticipated event that celebrates outstanding individual lecturers and the joy of scholarship, communication and community. Considerable effort goes into the delivery of this event and for that I thank the ever-present Diana Whithey for her administrative brilliance. Diana's standing up the back there. Wave to us please, Diana. Yes. I also thank successive generations of ANUSA leadership teams for their energetic custodianship of this event and of course all the ANU academics whose inspiring unforgettable teaching galvanises students to firstly nominate for this event, vote for them in the final ballot and then turn out today on the final Thursday to get one last taste of the winner's brilliance before year's end. No pressure, Jeanette. Our roll call of last lecturers so far is Chris Ruth Smith, Hugh White, Alistair Gregg, Paul Kerwin, John Hutchinson, Ben Wellings, Kieran Kirk and Ioannis Seogus. It is with great pleasure that I now hand over to the ANUSA President, Ben Gill, who will add the ninth name to that luminous list as he introduces the academic chosen by students to deliver the last lecture for 2015. Thanks Paula and good evening and welcome everyone. I would like to start by thanking those who made this event possible, similar to Paula. So thanks to Diana, Eleanor and Catherine. This event wouldn't be possible without you and the ANU community appreciates all the efforts for this event and more, though they can be a tad silent at times. This has been a huge year for students and the student association and I am grateful to have had the opportunity to have been involved to have been involved in its success. Our achievements have been many and varied and there is a huge array of diversity within that. We've increased engagement with our students through the introduction of the Fortnaylee newsletter, expanded our financial assistance program to more than what we ever considered possible than in 2014. Our autonomous departments have run some huge initiatives ranging from racism this week, the pledge talking about men's violence against women, Spoon Week, Climber Week and much more. The important thing to note is none of this would have been possible without the dedication and passion of students who have spent their year contributing to the ANU community. While there are hundreds and hundreds of students who made this happen, I would like to thank, in particular, the executive of a new cell. So my thanks go out to James Monique, Jack, Jock, Sophia and Megan for their challenge efforts to making this year what it has been. Now to introduce the academic staff member as voted by students to deliver the 2015 last lecture, Professor Jeanette Lindsey. A remarkable woman, Jeanette has obtained an Honours Degree in Geography, a postgraduate teaching diploma, and a doctorate in statistical and dynamical climatology from the University of Witt-Watersrand in Johannesburg. I had to practice that and it's on YouTube as well. If this wasn't enough, Jeanette has shared the Atmosphere Reference Group for the ACT Region State of the Environment Report, teaches by invitation at the United Nations University in Tokyo, holds a visiting professorship at the University of Tokyo, and is a senior fellow of the Higher Education Academy in the UK. Throughout her time at ANU, Jeanette has received numerous awards, including the 2006 ANU College of Science Award for Excellence in Teaching, the 2008 ANU Vice-Chancellor's Award for Excellence in Education, and the 2011 Citation for Outstanding Contributions to Student Learning. Now the really interesting thing is it's no surprise that why Jeanette's here today. I put a call out on social media trying to get some student sentiments and I found myself inundated with responses in a matter of hours. So while there's definitely not time to share a lot of them with you today, I've selected a few to share. So the first one is she's like an amazing researcher who actually generally cares about students. I've sat in class at meetings with her and everything that every student has said, she just completely soaked up. As well as being an amazing lecturer, she's really dedicated to teaching and mentoring students. She's the kind of person who publishes in the IPCC and still offers to turn up to student society events. The next one was she gave me a hug after I handed in my thesis, just a legend. There's also that right from my first year at ANU, Jeanette was one of the staff who helped me feel welcome and let me know I was a valued and respected member of the ANU community. This has lasted throughout my degree and into my PhD. I have a great deal of respect and admiration for her and she is one of my very favorite people to bump into the corridors. And the last one is just wanted to say that Jeanette has been not only a great passionate lecturer who always crams the most into every lecture, but she is also a really strong female role model and is still a male dominant research field in school. It's been really inspiring to be motivated by her. How could you not be passionate about climate change after talking to her? So there were many, many more, and I only chose to share a few. And I think it speaks a great deal about the impact that a lecturer can have on a student's lives and Jeanette has indeed had an impact on thousands of students lives. So with that, I would like you all to put your hands together and help me welcome Professor Jeanette Lindsey to present the 2015 last lecture. Thank you so much. And I must say when I received the advice that I'd been selected to give this last lecture, I felt quite overwhelmed because it's been my great pleasure to be involved in education for several decades and to be teaching here at the ANU for the last 22 years. And I just love it. But I guess one's not always sure whether the students appreciate it all that much. And it's just wonderful to know that one's efforts are being heard, seen and appreciated. And so it's an enormous privilege to be here tonight. What I'm going to share with you is some of my current thinking around the subject area that is what I do. And that is around climate change. I've made my career in climatology and in the research and education in that field. So I'm going to share with you a number of aspects of this topic. And I've chosen to call it on climate canaries and commitments. And I hope that the reason for that title will become clear as we go along. That should be somebody familiar to many of you. A wonderful communicator who I think does a fantastic job in communicating aspects of science to the public. And I picked up a couple of quotes from Neil deGrasse Tyson when I was preparing for this lecture. And there's one, the importance of science literacy, which is a point that I wanted to make right at the outset because I think this is vital for the future of humanity. We really need a scientifically literate population that is well enough informed to be able to make judgments about the issues that are put in front of them and able to make good decisions. So that's the first thing. And the second one is something that in the climate change area rarely rings quite true and close to home. The good thing about science is that it's true whether or not you believe in it. If I had to count the number of times I'm asked whether I believe in climate change and how I can convince people who maybe don't feel that way, well, it would be difficult to count all those instances. So I think science is really important. Not just science, but the scientific way of thinking, the scientific approach. And that doesn't only apply to the biophysical sciences where I work. It also applies to the social sciences. It applies to the ways in which we construct our thinking and the ways we think about problems and solving those problems. And that's what this refers to. It's all too easy, I think, to look at what's in front of us, to live as we do in our context and to take it as normal, to take it as the status quo, and that is what it is, so we accept it. What I think we should be doing as amongst the most educated people in the nation, in the world, we're all very privileged to be at this institution and to be getting degrees from here and working here, we should be questioning what's normal. We should be really questioning what is put in front of us, what we're surrounded by, and thinking about how it works, why it works, could it be different, should it be different? So what does normal mean? Well, in thinking about that, I thought, obviously I'm going to talk about climate. And climate has been changing. The animation that I had going when everybody was coming into the hall was a movie showing temperature data, and it was showing areas of the world that were cooler or warmer than the late 20th century average. And you could see, if you watched that over time, that starting off in the late 19th century, it was cooler and temperatures then increased as we came towards the present, and they continued to do so. What I've done here is take the most recent decade of temperatures, and from that I've subtracted the decade when I was born to have a look at what happened in my lifetime to global temperatures. And looking at that, it's quite clear that I probably didn't make the right decision to come into Australia because it's got warmer here than it has in Southern Africa, which is where I came from 22 years ago. So we see this pattern of warming with high temperatures, particularly rapid rates of warming in the Arctic and in other parts of the world over the oceans, the continents. There's this general signal of increasing temperatures, which is what we think about when we think about climate change. So I'm going to talk a bit about some of the aspects of climate change that I think are important. That's last year. So that's the temperature anomalies for 2014, and you can see that it's the Northern Hemisphere that's bearing the brunt of these higher temperatures at the moment, but we're seeing higher temperatures almost everywhere. There's a lot of inter-annual variation. You'll see cooler and warmer bits propping up here and there, but in general we've got this warming trend and then particularly warm areas in specific parts of the world. If we average all of that data and we make a graph out of it, we get a time series like this, which shows that the atmosphere is clearly warming and that we've had two main periods of increasing temperatures, one in the early 20th century and then a second in the latter parts of the 20th century and into the 21st century and that continues to the present and will continue into the future. It's likely the projections are that 2015 will be the warmest year on record. 2014 was the warmest year on record. You can see it just on the end of that over there. 2015 looks very much likely to surpass that given especially what's just happened in Europe in the last few months during the summer. So we've had about 0.85 over degree of global warming so far over this time period and in fact even if we extend it back a little bit and that 0.85 over degree of warming, so it's less than one degree, has led to significant impacts which I will say a little bit about, but we're not only getting atmospheric warming. We're seeing that the oceans are getting warmer too and this is of considerable concern. We tend to focus on the air temperatures because that's what we live in, but the ocean 73% of the Earth's surface, four kilometres deep, enormous amounts of water, absorbing heat from the atmosphere have been taking up between 80 and 90% of the excess heat that's being generated by human activities operating and affecting our atmosphere and that heat is being stored in the ocean as you see in this graph. Now that's setting up an enormous store of extra energy for the Earth's system which regardless of when we get on top of the atmospheric part of our problem is going to be there and we'll keep the warming going into the future for potentially centuries to come and that's something that we just have to accept, to realise that science is telling us this is how it is, oceanography has measured all of this and so that's what we have to deal with. How do we know that humans are part of this? Part of this is natural but part of it is us for sure and this is one of the bits of evidence for that. This is an influential paper published a couple of years ago now in the journal Science and what it shows is the last 12,000 years of temperature reconstructed relative to a late 20th century average, that's the zero line and you can see that while temperature becomes warmer and then cooler, those changes are very gradual, they take thousands of years to happen and that's natural, that's what the earth system does in response to various types of forcing mechanisms. What isn't natural is what's happened most recently in the last 150 years or so. So what we see in the last 150 years is a complete reversal and in fact exceedance of a cooling trend that had taken about 6,000 years to occur and this has happened in 150 years and that's what we see with us, that's what humans are doing to the global climate system and that's an indicator, it's one of the key indicators that we are indeed living in the geological epoch which is now being called the Anthropocene, you have heard of the Pleistocene and the Pliocene and the Eocene and all those geological eras of the past. Well we're now in a geological era which is significantly impacted on by humans, Anthropos and that is new. We've been developing over the last 250,000 years or more and we've now got to the point where we are a force of nature equivalent to the other significant influences on our planetary system. One of the key ways that we define this, one of the key ways that we measure what's going on is by measuring the carbon dioxide levels in the atmosphere. We burn fossil fuels when we clear land for agriculture, when we clear native forests and that sort of thing. What we're doing is emitting carbon to the atmosphere and that carbon combined with oxygen from the atmosphere and in fact oxygen levels are reducing at the moment so that's an interesting thing to think about, we need that to survive, we're not going to run out any time soon but nevertheless it is an issue. So we're seeing a rising trend of carbon dioxide in the atmosphere and it has a very characteristic pattern which I won't go into too much but what we find is that the levels of CO2 in the atmosphere currently are around 397.6 parts per million, that's the most recent figure for September, last month. We went over 400 for six months of this year, it was three months in 2014 and it was one month in 2013. In a couple of years time we'll be over that 400, now that's not a physical significant number it's a number that I think has a kind of psychological importance, it's a round number and that's the sort of thing we tend to pay attention to but there's this inexorable upward creep of the carbon dioxide in the atmosphere as well as the other greenhouse gases that trap heat and cause warming. What's significant about this of course is that the naturally occurring variations of carbon dioxide in the atmosphere over the last million years or more have varied between 180 and 280. Now we're at 400 and climbing and that is not natural, it cannot be natural, it's us. That's a 43% increase over any peak that had been experienced over the last million years due to natural factors. That's led to a great deal of concern and scientific effort through the International Geosphere Biosphere Programme that began in the 1980s and then through the developing Future Earth Programme which is beginning and is taking shape and that effort has been focused on looking at what I think you could refer to as the canary in the coal mine and that's where the canaries comes from in my title. We have a number of things that are happening in our environment that are acting I think as canaries and we should really be paying attention. For those of you who don't know about this in old days before we had chemical sensors, miners in coal mines used to take bird down with them into the coal mine because if there was methane in the air that was toxic then the canary would succumb and they would realise when they found it at the bottom of the cage with its toes turned up that maybe they should get out of there because there could be a methane gas explosion or poisoning. So there are a number of things that are happening in our global environment that warn us about what's going on with climate change and I just want to talk about a couple of those. We're aware that we've got a very big El Nino event happening at the moment. It's one of the strongest events on record. It started developing in about April of this year and it's not yet peaked. It's liable to peak around December and that map shows you the sea surface temperature anomalies across the world and you can see very clearly here this big pool of warm water in the Pacific. I'm going to talk very briefly about Hurricane Patricia in a minute and I'm going to talk a little bit about the waters that Patricia would have formed over these warm waters here. This warm water gives energy to the atmosphere and to weather systems and so what we've got here is a large area of the Pacific Ocean which is up to three degrees above average. Below the surface at about 100 metres down the ocean is six degrees warmer than average in that part of the world and that makes an enormous energy store which is going right through into next year after it reaches its peak around the end of the year. And of course in Australia we know that most strong El Nino events are associated with below average rainfall as they are in southern Africa, in India and in areas to the north of Australia which I will mention in a minute. A point I wanted to make about this is that these anomalies of temperature are expressed relative to a time period from 1981 to 2010 and that time period 1981 to 2010 already has a higher average temperature than say the previous 20 year period if we went from 1960 to 1980 for example. And so what we're seeing is rising averages and anomalies expressed relative to a higher average the whole thing is shifting upwards if you like into this warmer ever more energetic environment. The impact of this on Papua New Guinea is severe. The monsoon is late it hasn't yet eventuated and so large parts of PNG are in drought as shown in the map in all those red areas those are areas in severe drought and because the skies are clear and as you may be aware PNG is a highly mountainous country in the mountainous areas they're having frosts at night because the skies are clear so the temperatures drop below freezing there's not enough water they're in drought the crops are failing because there's a lack of rainfall and lack of water and then what crops do grow and these are food mounds are being killed by frost these are dead sweet potato vines That's in PNG in Indonesia you might have heard about the haze problem there's a serious haze problem in Southeast Asia at the moment Singapore for example is very concerned about this and these fires are occurring because of agricultural activities in Kalimantan and Sumatra some of this is about forest clearing and some of it is about agriculture it's threatening wildlife it's causing enormous air pollution problems and the air pollution is affecting more than 500,000 people at the moment and those are reported cases and respiratory distress reporting to hospitals the PSI is a measure of air pollution loading anything above 300 is considered to be dangerous and it's currently up above 2,000 in this region so this is because of the El Nino drought the last time we had fires of this severity and this extent through Indonesia was the 1997-98 El Nino the daily emissions from these fires of the daily emissions from the entire US economy and that's being transported around the Southeast Asian region at the moment reached the Philippines the other day globally associated with these higher sea surface temperatures we're seeing a global coral bleaching event coral bleaching occurs when the sea temperatures become so warm that the coral organisms can't survive and so you are left with the dead coral skeletons the coral organisms are no longer there what we're looking at in the photograph is pictures from American Samoa in the Pacific December 2014 and February 2015 after an extensive bleaching event so that's a healthy reef and that's a bleached reef this is only the third such global event that we have on record it's associated with the combination of the El Nino and the global warming trend and we should remember that the reefs support 25% of all marine species so they're an incredibly important part of the ocean ecosystem the areas that are shown in dark red in that map are the ones where there's at least a 60% probability of coral bleaching this year between October now and January of 2016 if we go to the Arctic I showed you that map with the high temperatures but if we look at the Arctic there's large areas shown here of permanently frozen ground now that permanently frozen ground is predominantly peat bog which has been frozen for thousands of years tens of thousands of years in some cases and that peat is vegetation which has rotted in an anaerobic environment and then become frozen there's a lot of carbon there and there's a lot of methane which is trapped in that peat the permafrost is melting and it's starting to release methane and it's also causing problems so there's lots of photographs if you have a look on Google of things like collapsing roads and oil pipelines and trees, this is the Denali Wilderness National Park the drunken forest where the trees are all falling over because the solid ground is no longer solid, it's melting the most recent bit of information about this is that in parts of the Arctic we're seeing the warming occurring at 0.1 of a degree per year and that is contrasted with an average rate of global temperature increase of 0.2 degrees per decade so we're looking at a degree per decade in the Arctic relative to 0.2 degrees it's an order of magnitude faster what is happening in the Arctic and of course the Arctic sea ice is also diminishing in extent particularly in the summer and that has led to the opportunity for New World Records so this team which is a team from China, Germany, Russia and France set a new record in sailing from Murmansk in Russia around the northeast passage which basically goes along the sort of northern edge of Eurasia in 13 days to reach the Bering Strait that is a new world record they've put it up to beginner's book of world records and they're able to do it because the ice isn't there anymore you would not have been able to do this five years ago you certainly wouldn't have dreamt of doing it ten years ago shipping companies are building container ships to traverse the Arctic to get between Asia and North America much shorter and much cheaper than going via Panama etc those ships will be ready in the next year or so on the fact that that shipping route will be available and that's an opportunity in the tropical Pacific moving away from the Arctic this year we had a record three category four cyclones in the Pacific at the same time there they are and that was back in August that's the first time that's ever been observed the most we've had before is two category threes at the same time, five is the maximum three category fours that means there's an enormous amount of energy available or else these storms couldn't function and that energy is provided by a generally warmer ocean and the El Nino event on top of that most recently last week Hurricane Patricia which impacted on the coast of Mexico Hurricane Patricia started off as a tropical depression as these storms do fairly minor tropical storm it blew up to a category five hurricane in 24 hours that is if not unprecedented extremely unusual they usually develop over a number of days as they track over the warm ocean it's likely the most severe hurricane on record it had winds of up to 325 kilometres per hour they could have been stronger but that was the strongest that was measured and the central pressure of 879 hectopascals which for those of you who haven't been sitting in my lectures and haven't noticed this stuff that's pretty low average sea level pressure is 1013 so this is low the lowest ever measured is 870 so very close to lowest possible pressure and it was pure luck that we didn't have more deaths and more damage from this particular event it happened to pass between two cities rather than going over one of those and so the damage was somewhat minimal which is a blessing so we're being told something here the environment is telling us multiple chirpings and tweetings and twitterings that there's something going on and I don't tweet I have to say this is the extent of my tweeting what are we doing about it we're getting the message I think the global community is starting to get the message and sometimes that message is transmitted by an extreme event it's submitted by a typhoon impacting on the Philippines it's Hurricane Patricia possibly the strongest on record it's the melting of the ice it's all of those events it's the heat waves in India the 3000-4000 excess deaths that occurred in India just this year minimum because of the delayed monsoon and the extreme heat it's the heat that we've seen in Europe and the issues that that has led to here is an example of the sort of thing that I think is starting to really make a difference in the way that society is starting to pay attention to this issue this is a graph from a report called the new climate economy which I would highly recommend you have a look at and it talks about the costs of mortality deaths due to air pollution where the majority of the air pollution is a result of the combustion of fossil fuels in power stations in motor vehicles and so on what you see you may not be able to read it clearly but this is percentage of GDP by in a number of countries the one that's experiencing the brunt of this at the moment is China where between 11 and 12% of GDP in 2010 as a result of mortality due to air pollution and it's not a surprise given the amazingly difficult and problematic air quality issues that China is faced with that China is now amongst one of the leading countries in introducing strategies to roll out renewable energy on a large scale you may recall during the Beijing Olympics there was a lot of coverage of the fact that industries were shut down for the month leading up to the Olympics to clear the air so that the athletes and the spectators would have a better experience and then we've got the Russian Federation India, Germany, Korea and so on all above 5% of GDP lost and then coming down to other countries like Mexico, Canada Indonesia, Brazil, South Africa putting a price on these sorts of climate related costs to the community I think is an important thing to do I used to think that being a pure scientist that putting a price on the environment was maybe not the right thing to do it's difficult to do environmental goods and services are difficult to cost difficult to value and I wasn't sure that it was actually the right thing to do but I think in seeking to address climate change and the other major environmental issues that we're facing we really have to because this is how the world works it works on the economy and that's where we have to really make inroads on getting action a recent paper that was published just last week in the journal Nature looks at climate impact on GDP, global GDP gross domestic product the highlights out of that paper from my point of view were the first of all that it highlights the inequities what they found is that there's a sort of sweet spot of temperatures within which agriculture flourishes and economies operate well and you don't have a lot of excess death due to heat stress and that sort of thing and that range of temperature tends to apply in the mid-latitude countries of both hemispheres the impacts of global warming are therefore going to be greater already greater in the countries that are warmer which tend to be around the tropics mostly the developing countries what the paper also showed is that the cost of inaction of not doing something to mitigate climate change would be a likely decrease of GDP of 23% by 2100 by the end of the century so a hit of about a quarter of what GDP would have been without climate change the cost of mitigating climate change of doing the sorts of things that I'm going to talk about very briefly in a minute are calculated at about 1.6% of GDP by 2050 some work just recently done by colleagues at CSIRO Heinz Schundl and Steve Hadfield Dodds it's pretty obvious that it's much cheaper to act to reduce emissions and to get on top of climate change than it is to do nothing but it requires long term thinking and that's something that doesn't come to many people very easily so how do we respond these are just a few of the ways that we are responding or are thinking about responding population growth and economic growth are very much the fundamental drivers of what we are seeing expressed as global warming and climate change how palatable is it to have a societal discussion about limiting population or limiting economic growth not very in fact not at all however we can talk a bit about changing lifestyles and consumption it's not a popular societal discussion a lot of people feel threatened by this but really do we need an iPhone 6S when the iPhone 5 fine last a few more years so consumption is really important consumption is critical we could do and have with much less and have wonderful quality of life so that's something that we need to do more about I think and we need to have that discussion and see how we can progress individuals, groups communities are moving in that direction and that's great we should do already attempt to manage our products, the forests agriculture and so on that's where the carbon is stored and that's where it needs to be maximised are we doing enough no we're not the very last thing we should be doing is clearing old growth forests replacing an old growth forest with a plantation or with agriculture is never going to replace the carbon that is stored in that forest so that's a no brainer and that's where in the climate change there's no space strategies like red plus reducing emissions from deforestation and forest degradation become important so there's more to do there improving energy efficiency this is one that we've actually got a bit of a handle on it's going pretty well places like California have wonderful energy efficiency standards for buildings and so forth we're doing work on this in Australia it started off with energy efficient appliances and it's been rolling out so we could do this as well but we could do more that means of course you reduce the future demand for electricity, for energy and that helps in terms of emissions we could decarbonise energy production that would be a really interesting idea that's one that we really can do and I'll say a bit more about that in a minute if we don't do any of those things and the other sorts of strategies that might be available to us and we do end up heading towards the higher end that we might be facing over the next 1800 years or so then the possibility is that we will be tempted to further geoengineer the earth system we are already geoengineering we build large hydroelectric dams for instance we put carbon and methane and nitrous oxide into the atmosphere and raise the temperatures these are all aspects of geoengineering deliberate geoengineering to tackle climate change might involve putting pollution into the stratosphere sulphate aerosol to block the sun and cool the surface it might involve putting mirrors in space to reflect sunlight and keep the surface cool it might involve seeding the oceans with iron to create blooms of plankton that would suck the CO2 out of the atmosphere but would also suck the oxygen out of the ocean and kill marine life so I was very struck when we first moved to Australia by the story of the Cane Toad I'm sure everybody here is very familiar with the story of the Cane Toad it just illustrates to me that humans have a pretty poor record of looking at a problem coming up with the obvious solution implementing that solution and then discovering that it actually wasn't such a good idea after all but I'm sure that all of you will have wonderful ideas have wonderful ideas and have the potential to contribute further solutions and that's what we would be looking to you for so what are we doing? Well as a global community we are negotiating and we are attempting to reach agreement on reducing emissions beyond 2020 these are the countries that have pledged various forms of emission reduction beyond 2020 for the Paris conference of the parties of the United Nations Framework Convention on Climate Change 126 countries have made pledges and that covers 86.5% of all of the emissions at the moment so this is pretty good that we've got a lot of buy-in most of the countries in the world have committed that they're going to practice some kind of emission reduction the thing that I think is disappointing is that all of this reduction will begin to happen after 2020 it's not going to happen immediately and the problem that the challenge is urgent and needs urgent response so can we do it? Well I think we possibly can that little window is maybe closing but it's still open and that's cause for hope cause for optimism this is an analysis done by it's called the Climate Action Tracker it's on the World Resources Institute website what it shows is that the IPCC the Intergovernmental Panel on Climate Change shows that emissions could rise as high as this by the end of the century with 4 to 5 degrees of global warming by 2100 if we do nothing and just keep on going business as usual if we follow the current policies that are in place in countries around the world we'll be heading for between 3 and 4 degrees the commitments that are on the table for Paris if they're implemented effectively will take us to between 2.5 and 2.7 degrees where we are aiming to get is no more than 2 degrees that's the global policy target and if you are a small island state in the Pacific or the Indian Ocean the Maldives or Tuvalu or Kiribati then 1.5 degrees sounds an awful lot better 2 degrees is too much so we're on the right track the pledges in Paris are not enough to get to where we want to go but they're heading in the right direction and they're certainly better than if we simply continued with the sorts of things that we've got in place at the moment so there's more work to do can we do it? yes I think we can this graph shows carbon emissions over time from 1960 to 2012 I think it is and it shows how every time we have a financial crisis the emissions slow down because there's a slowdown in global economic activity so the two are really tied to each other do we want to have a continuous financial crisis in perpetuity? no of course not so that's not the answer but the answer could be should be that we decarbonise our energy and our global productivity our global wealth production the graph shows the carbon intensity what it is is how much carbon is emitted for every dollar of gross domestic product every dollar of productivity in the world that's generating wealth and you can see how that is starting to flatten out since about 2000 it's shown significant signs of flattening and that is very encouraging because it means we still have economic growth but we are not using as much carbon to achieve it so what we need to do with the energy net is by managing how we produce energy largely there's land management in here as well forest management and agriculture and so on but a lot of it has to do with energy production that's satellite data the world at night showing of course where all of that energy is being used in North America Europe, India continues to develop and the global population continues to grow we expect that those dark areas would want to be filled in to a large extent the lights will spread but where is that energy going to come from let's look at what we're doing in Australia electricity consumption in Australia peaked in 2009 since then it's been falling this little graph shows it and it's been falling for a variety of reasons but some of it has to do with the fact that more than a million homes in Australia now have photovoltaic panels on their roofs and are generating more power often than they're using and putting that power back into the national electricity grid South Australia is generating nearly 40% of its energy now with wind and solar Brisbane earlier this year and South Australia this year and last year reached 100% renewable supply so completely covering all usage for brief periods this year and last year so a whole state which includes industry and everybody's living and all the rest of it able to reach 100% renewables I saw an example at a guest lecture that was given in my course just this week which showed that when the last remaining coal-fired power station in South Australia experienced a fire and they had to shut it down for a while the renewables just took over and nobody noticed that the coal-fired power station wasn't there they have a graph to prove it but it's possible and we're doing it South Australia now has a new target for their renewable energy of 50% by 2025 and all the projections are that they'll reach it probably by 2020 and they'll then be able to ramp it up because they have a flexible policy in this regard the ACT right here has 100% renewable energy target by 2025 and we're well on track to achieve it so it's doable, we have the technology we don't need anything new in order to make this work it can be done in the developing countries it can be done in the developed countries many countries are already well on the way and that's why it's hopeful that's plan A that we work to preserve this and to have a liveable home and a beautiful and biodiverse and wonderful home for humanity that's plan B that's plan B but it's not really a plan at this stage we all know that it wasn't really easy just even for one person and is it worth it you'll always hear about the costs but it's going to cost us jobs or it's going to cost us money to make these changes that we need to make the structural changes in the economy that sort of thing, is it worth it well absolutely it's worth it and what if all of the science that I've spent my career working on and the thousands and thousands of climate scientists and other environmental scientists around the world what if we're wrong what if the intergovernmental panel on climate change is wrong and climate change is not really such a big deal and we're not heading for four degrees of warming well you know we'd have energy independence and sustainability and liveable cities and clean water and healthy children and food security and so on and so on so it seems like a win-win as far as I'm concerned I started off with Neil deGrasse Tyson and I thought I might end with him the dinosaurs never saw the asteroid coming so what is our excuse we have no excuse we know what is happening you all know and it's up to us to do something about it and it's wonderful to know that we are doing something about it we just need to act on this more rapidly and I think with more leadership let's say nationally, locally internationally thank you I don't think we're going to let you escape that easily good evening I'm Chris Wilson, the president of ANU's Postgraduate and Research Students Association here representing the 11,000 postgraduate students and unofficially Neil deGrasse Tyson who unfortunately were unable to make it here today the next generation are always looking for demons to slay and in times past our best and brightest could be found conducting field training at Santhurst or sitting in the back benches of Capital Hill yet now they are conducting field work around the world for the colleges of this university or sitting in our laboratories and theatres being inspired by world leaders such as Professor Lindsay the demons I mentioned were formally philosophical or spiritual but as Professor Lindsay outlined and has spent her considerable career investigating the biggest demon the existential demon is climate change whether you believe it or not its importance is again shown here by the selection of Professor Lindsay to deliver our last lecture yet it's more than the topic that brought the professor here it's her teaching manner the support she shows countless students but above all it's the excellence she demonstrates every day as your lecture today has shown and through the large attendance from students and distinguished staff alike in this room and those listening online in the future there is nobody here at ANU who is too cool to be a fan of yours before I deliver the closing ode I would like to invite everyone here to celebrate the close of the academic year by joining us in the courtyard for some light refreshments following our exit the traditional ode to the end of the last lecture written by Laura Crespo in 2006 signifies the formal close of the last lecture it seems a welcome irony that we look so gratefully to the end to this academic year but still take the effort to listen to this one last lecture we have no obligation no monetary or assessment like intent but we still fill this hole not afraid to learn and give we demonstrate respect for this institution of learning and the values that it brings collegiality commitment pride responsibility freedom service dismental the study places those crook nook and cranny like retreats and stand with me and thank Professor Lindsay as she exits this hall and thus ends the 2005 academic year