Quick-and-dirty summary of global warming

22 06 2013

Due to the senseless lies propagated by a minority of very vocal global warming denialists, there is a lot of misinformation and ignorance among people about the current phase of anthropogenic global warming. So, this post is a down-to-the-basics summary of global warming.

In a nutshell, carbon dioxide is a greenhouse gas. Its concentration in the atmosphere is rising due to additional input from human sources, causing the greenhouse effect to get intensified and the Earth to get warmer.

This is not a new-fangled insight. In fact, back in 1824, Joseph Fourier calculated that heat from the Sun is not enough to keep the Earth as warm as it is. There must be some other effect, and he surmised that the atmosphere also helped with keeping the planet warm. This was the greenhouse effect – just as the glass of a greenhouse keep the interior warm by trapping the Sun’s heat, so does the atmosphere.

John Tyndall discovered how the atmosphere does this in Tyndall (1859). There are gases in the atmosphere, notably water vapour and carbon dioxide, that allow sunlight to pass through them, but absorb infrared. Infrared is heat. So what happens with the Earth? Sunlight goes through the atmosphere, hits the ground and warms it up. As a result of this warming, infrared light is emitted, but the greenhouse gases absorb them instead of allowing them into to space. In other words, the heat emitted from the ground is trapped. In addition, the warming of the greenhouse gases also causes them to emit infrared, so there are two sources of warming.

So by the mid-1800s, the greenhouse effect’s existence and basic functioning was settled. The next step in our understanding came from famous chemist Svante Arrhenius in 1896. In Arrhenius (1896), he calculated that increasing CO2 concentrations will lead to an increased warming effect, and went further by saying that the burning of fossil fuels, by injecting CO2 into the atmosphere, is going to cause increased warming.

Fast forward to the modern era, and this prediction is confirmed. Starting from Keeling (1958) and in tons of studies since then, atmospheric CO2 has been measured in great detail and in all places and situations around the world. Carbon dioxide levels are, beyond the shadow of a doubt, rising yearly.

nasatemp

Concurrent with this, and agreeing with Arrhenius’s prediction, the instrumental records from land surface stations, sea surface readings, boreholes, ice cores, balloons, and satellites all show the average global temperature increasing by the year, tracking the increases in CO2. Hence, we can say with confidence that the Earth is warming, and it’s due to human influence, as the current major source of the extra CO2 is traced back to the use of fossil fuels. In essence, what we are doing is restoring the atmosphere of that was present when the fossil fuels formed (especially the Carboniferous coal swamps), and that’s bad because the infrastructure of human civilisation evolved at a time when CO2 levels were very low – adapting to a high CO2 world is going to take drastic changes.

Of course, there are many more greenhouse gases. But carbon dioxide is the one that’s emitted the most, hence why we concentrate on it.

The world is changing due to our inadvertent messing around with the climate. The ice caps are slowly melting – we will soon be able to have an ice-free Arctic in the summer (which will have many knock-on effects on the world climate). The biosphere is reacting dynamically to the changes, with phenologies and migration patterns changing, which is leading to the infilitration of tropical diseases into temperate zones. Ecosystem zones are shifting, with deserts and treelines expanding.

The land that we depend on to sustain human civilisation through agriculture is disappearing at alarming rates. In the 1970s, 12% of the Earth was classified as very dry. Now it’s over 30% (Dai et al., 2004), and it’s not stopping there.

Some say that citing such statistics is deceptive, as the Earth doesn’t care. Of course the Earth doesn’t care. The only thing that is at jeopardy here is human civilisation (and countless species, but let’s keep it close to heart). The only reason why we harp on about global warming is so that we may be able to continue prospering as a species on this planet. We need to change our lifestyles, we need to ramp up technology and revitalise agriculture with widespread GMO use, we need to switch to clean energies (nuclear, then renewables) to mitigate greenhouse gas emissions. These changes cannot wait any more, they need to happen now. Actually, they should have happened decades ago, but hey, who listens to scientists anyway?

Further Reading:

I have listed several of my favourite books on climate and environmental issues here and here. An excellent website to check out and blog to follow is RealClimate.

References:

Arrhenius S. 1896. XXXI. On the influence of carbonic acid in the air upon the temperature of the ground. Philosophical Magazine Series 5 41, 237-276.

Dai A, Trenberth KE & Qian T. 2004. A Global Dataset of Palmer Drought Severity Index for 1870–2002: Relationship with Soil Moisture and Effects of Surface Warming. Journal of Hydrometeorology 5, 1117-1130.

Fourier J. 1824. Mémoire due les températures du globe terrestre et des espaces planétaires. Annales de Chémie et de Physique 3ème série 27, 136-167.

Keeling CD. 1958. The concentration and isotopic abundances of atmospheric carbon dioxide in rural areas. Geochimica et Cosmochimica Acta 13, 322-334.

Tyndall J. 1859. Note on the Transmission of Radiant Heat through Gaseous Bodies. Proceedings of the Royal Society of London 10, 37-39.





Top Books of 2012: Environmentalism and Climate Change

20 12 2012

Jump to another list: Evolution; Historical Geology; History of Science; Human Evolution and Anthropology; Palaeontology; Zoology

Welcome to the first post of my “2012 in review” series, which will have one post every day for the next 2-3 weeks. The first 7 posts will be lists of the top 10 books of the year for a specific category: Environmentalism and Climate Change; Evolution; Historical Geology; History of Science; Human Biology; Palaeontology; and Zoology (ordered alphabetically). These will be followed by top 10 discoveries/papers of the year in all the fields I usually cover, topped off with an absolute top 10 discoveries, and finally a review of the blog’s progress in 2012 and future outlook.

Anyway, let’s start off with the environmentalism books. I use “environmentalism” as an umbrella term for all the important issues we’re facing today that are associated with a changing environment and its impact on the bio- and anthroposphere, including climate change, extinctions, and energy production. The books include only academic and popular books, not standard textbooks.

  1. Weart. The Rise of Nuclear Fear. (Harvard University Press)
riseofnuclearfear 2011 saw one of the strongest natural disasters in history hit the coast of Japan, but the media and populistic fallout from it was far worse than any purported nuclear fallout. If there is one word to summarise it, it would be “ridiculous”, especially in this day and age when the only way out of our mess is to let go of silly emotional arguments and embrace facts – and the facts are clear that nuclear power is one of the safest ways to make energy, and by far the best transitional energy source until we get renewables properly sorted out. This book examines the historical and cultural backgrounds to the hysteria behind the anti-nuclear movement and in so doing, provides an objective resource to the pros and cons of nuclear energy – it chastises the exaggerations made by both sides.

  1. Berezon & Campbell. Science Left Behind: Feel-Good Fallacies and the Rise of the Anti-Scientific Left. (PublicAffairs)
antiscienceleft My ranking this book as #2 should tell you just how much I despise what I see as a profoundly anti-scientific environmental movement. It’s so pervasive and embarrassing that I hesitate to call myself an environmentalist, because I know I’ll be lumped in with nature-worshipping and science-ignorant New Age hippies – an attitude commonly seen on the left side of the spectrum, both in Europe and apparently in the USA too. This book is Americentric, and it focuses generally on science denialism, but the attitude is one that affects environmental issues too, hence my categorising it here.

  1. Stone. The City and the Coming Climate: Climate Change in the Places We Live. (Cambridge University Press)
cityclimate There are many books that deal with climate change generally and its impact on the biosphere and human health, but this one is unique by concentrating on how the effect of climate change is amplified in cities, and how this will affect our urban lives, and makes a very strong point that even if we manage to reduce our greenhouse gas emissions, we will still be forced to do permanent changes to our lifestyles in order to be sustainable.

  1. Seidl. Finding Higher Ground: Adaptation in the Age of Warming. (Beacon Press)
8598 This is actually a 2011 book but was only released in paperback this year, so I’m sort of cheating by putting it here. It deserves it in any case. Book #3 made the point that climate change is going to affect our lives no matter how much we curb our emissions. This book links up with it thematically by giving examples from both human history and the biosphere on how to adapt to climate change. Even if you don’t care for that theme, the compendium of information itself is useful, if only as trivia.

  1. McKibben. The Global Warming Reader: A Century of Writing About Climate Change. (Penguin Books)
the-global-warming-reader-a-century-of-writing-about-climate-change This book is an anthology of the essential writings on climate change, collected by one of the leaders of the field. They range from purely academic accounts, to call to arms, and even include some of the skeptical views for good measure. If you need a resource on thoughts on climate change and their history, the development of the science behind climate change, or just answers to your questions with a historical twist, then this book is for you.

  1. Sale. Our Dying Planet: An Ecologist’s View of the Crisis We Face. (University of California Press)
our-dying-planet-an-ecologists-view-of-the-crisis-we-face There are relatively few books on climate change written by those who experience and research it first hand, and this book fills the gap perfectly, giving a perspective from the point of view of a coral researcher, i.e. from someone who researches the ecology of one of the most climate-sensitive organismal groups on Earth. This account gives the issue of climate change a tangible sense of what is ecologically at stake, away from the usual statistics on atmospheric conditions and tales of political and social inaction.

  1. Boyle (ed.). Renewable Energy: Power for a Sustainable Future. (3rd ed., Oxford University Press)
414lKy7pYWL._SL500_AA300_ I know I said no textbooks, but it would be a shame if I left this list with no book on renewable energies, and this 3rd edition of Renewable Energy is the gold standard. It’s UK-centric, but when it comes to information about the actual technology and possibilities, it’s up-to-date and applicable for any country. It’s at an undergraduate level too, so it doesn’t take much to get a hang of it – and the excellent diagrams will make sure you can grasp any concept presented.

  1. Cowie. Climate Change: Biological and Human Aspects. (2nd ed.; Cambridge University Press)
170544329 Every year sees the release of an excellent academic text on climate change summarising all aspects of what we know. This is this year’s version of that book, and it’s a useful tome for anyone looking for the most current and up-to-date resource book on climate change.

  1. Rogers, Johnston, Murphy & Clarke (eds.). Antarctic Ecosystems: An Extreme Environment in a Changing World. (Wiley-Blackwell)
1405198400 This is the most expensive book that will be in any of the lists, and I arguably shouldn’t even have included it because it’s beyond the reach of most, and it’s not really focused on environmental issues. I decided to put it in here for two reasons: it’s the best available summary of Antarctic biology and ecology, and I personally view Antarctica as one of the most ideal places to observe the effects of environmental change, a view that is reinforced time and again in all case studies discussed in the book. If you’re a working biologist interested in climate change, you should try and find this book (preferably through an institutional library to not break your bank account).

  1. Alcamo & Olesen. Life in Europe Under Climate Change. (Wiley-Blackwell)
{C117E825-4FEF-477F-B8D2-01796E4392C1}Img100 The book that rounds off the list is Eurocentric, focusing on how the climate will change in Europe and those changes’ effects on European cities. Spoiler alert: things don’t really look good except for Northern Europe, and there will be changes even there. While the specifics of the climate changes described are only applicable for Europe, the sustainability and adaptability themes are applicable globally for developed countries, so you might find a use for the book even if you’re not European.

Jump to another list: Evolution; Historical Geology; History of Science; Human Evolution and Anthropology; Palaeontology; Zoology





Palaeoclimate Analogs to Modern Climate Change: The Mid-Late Cretaceous

20 08 2012

The Cretaceous has long been known as a very warm time of Earth’s history. Lyell (1837) pointed out the presence of Cretaceous chalk as far north as Denmark and Sweden as indicators of warm northerly oceans. This is now more reliably hinted at by the presence of vegetation at polar latitudes (Creber & Chaloner, 1985) – trees can’t grow on ice, so if they’re present on a polar landmass, it must have not been covered by an ice sheet. The Late Cretaceous is indeed the warmest period of Earth’s history from the past 144 Ma.

For the early Cretaceous, one can take the climate of the well-studied Wealden Beds of southern England as exemplary of the general global climate. There was a seasonal climate alternating between fairly warm average temperatures of 25°C and going down to cooler 10°C (Allen et al., 1998), with temperatures going as high as 40°C and as low as 4°C, respectively (Haywood et al., 2004). Elsewhere on the globe, there were some arid zones and some humid, tropical zones, as well as glaciated poles. It wasn’t identical to today, but similar at a general level, just a bit warmer and wetter.

The mid-Cretaceous saw one of the more dramatic climate transitions in the history of the Earth (Hay, 2011) with temperatures becoming 6-14°C warmer (Barron, 1983). Increased volcanism led to higher levels of CO2 and caused the appearance of a greenhouse climate where even the poles experienced average temperatures between 13 and 20°C on ocean and land, respectively (Jenkyns et al., 2004). The Arctic was populated by crocodile relatives (Tarduno et al., 1998), and since modern crocs don’t live in freezing temperatures, it’s inferred that the Arctic must have been at least temperate.

The mid-Cretaceous transition enabled proper temperate forests to emerge where now there is only tundra or ice (Spicer et al., 1993). This expansion of forests then led to a positive feedback reinforcing the warming trend to form a supergreenhouse in the Late Cretaceous, since the forest cover lowered the albedo of the land and thus helped heat retention (Upchurch et al., 1998).For an example of how the climates of the time were, one can look at the Two Medicine Formation in the USA, where tree rings indicate the exact same kind of climate in the Western Interior of the USA as in East Africa today (Falcon-Lang, 2003).

In the Arctic, it was warm enough that there was only some sea ice in winter, but otherwise it was all ocean (Davies et al., 2009) – the same state we are expecting to have by the next 50 years (Holland et al., 2006). This is why the Cretaceous is a good palaeoclimate analog to modern global warming, especially for studying the effects of having no polar glaciation. It’s also an effective testing ground for the accuracy of climate models. It has long been a problem that climate models taking only CO2 levels into account underestimated the true magnitude of the warming, leading to the refining of climate models to include other factors, including circulation patterns, ocean temperatures, geography, topography, and other  parameters to make the models more accurate. These lessons are then applied into modern climate modelling, leading to the very precise models used nowadays.

References:

Allen P, Alvin KL, Andrews JE, Batten DJ, Charlton WA, Cleevely RJ, Ensom PC, Evans SE, Francis JE, Hailwood EA, Harding IC, Horne DJ, Hughes NF, Hunt CO, Jarzembowski EA, Jones TP, Knox RWO’B, Milner A, Norman DB, Palmer CP, Parker A, Patterson GA, Price GD, Radley JD, Rawson PF, Ross AJ, Rolfe S, Ruffell AH, Sellwood BW, Sladen CP, Taylor KG, Watson J, Wright VP, Wimbledon WA & Banham GH. 1998. Purbeck–Wealden (early Cretaceous) climates. Proceedings of the Geologists’ Association 109, 197-236.

Barron EJ. 1983. A warm, equable Cretaceous: The nature of the problem. Earth-Science Reviews 19, 305-338.

Creber GT & Chaloner WG. 1985. Tree growth in the Mesozoic and EarlyTertiary and the reconstruction of palaeoclimates. Palaeo3 52, 35-59.

Davies A, Kemp AES & Pike J. 2009. Late Cretaceous seasonal ocean variability from the Arctic. Nature 460, 254-258.

Falcon-Lang HJ. 2003. Growth interruptions in silicified conifer woods from the Upper Cretaceous Two Medicine Formation, Montana, USA: implications for palaeoclimate and dinosaur palaeoecology. Palaeo3 199, 299-314.

Hay WW. 2011. Can humans force a return to a ‘Cretaceous’ climate? Sedimentary Geology 235, 5-26.

Haywood AM, Valdes PJ & Markwick PJ. 2004. Cretaceous (Wealden) climates: a modelling perspective. Cretaceous Research 25, 303-311.

Holland MM, Bitz CM & Tremblay B. 2006. Future abrupt reductions in the summer Arctic sea ice. Geophysical Research Letters 33, L23503.

Jenkyns HC, Forster A, Schouten S & Sinninghe Damsté JA. 2004. High temperatures in the Late Cretaceous Arctic Ocean. Nature 432, 888-892.

Lyell C. 1837. On the Cretaceous and Tertiary Strata of the Danish Islands of Seeland and Möen. Transactions of the Geological Society of London, Series 2 5, 243-257.

Spicer RA & Corfield RM. 1992. A review of terrestrial and marine climates in the Cretaceous with implications for modelling the ‘Greenhouse Earth’. Geological Magazine 129, 169-180.

Spicer RA, Rees PM, Chapman JL, Jarzembowski EA & Cantrill D. 1993. Cretaceous Phytogeography and Climate Signals. Phil. Trans. R. Soc B 341, 277-286.

Tarduno JA, Brinkman DB, Renne PR, Cottrell RD, Scher H & Castillo P. 1998. Evidence for Extreme Climatic Warmth from Late Cretaceous Arctic Vertebrates. Science 282, 2241-2243.

Upchurch GR Jr., Otto-Bliesner BL & Scotese C. 1998. Vegetation–atmosphere interactions and their role in global warming during the latest Cretaceous. Phil. Trans. R. Soc. B 353, 97-112.





Climate: The very basics

7 09 2011

I know, this is a biology blog. But, well, all organisms live on Earth and have always been influenced by climate (how do you think humans managed to spread across the Earth?). In this series, we will look at the history of Recent climate (since 1 Ma ago) and its future (and perhaps later, I’ll do the entire history – I’ve already done the Neoproterozoic anyway). In this post, I just want to introduce the very basics of climate science, the prerequisites that you need to know to understand the rest of the series; chances are you already know all the info in this post. Read the rest of this entry »








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