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    • Rights: Thin Ice/University of Waikato
    Published 11 April 2017 Referencing Hub media
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    Dr Nancy Bertler explains how ice cores1 are sampled for chemical and isotopic analyses for past temperature2, wind, sea ice extent, snow source and other variables.

    Transcript

    Dr Nancy Bertler

    Everything that you see on a periodic table3, everything that’s in the atmosphere4, everything that’s being breathed or evaporated out of the oceans, dust that comes off the continents5, we find literally everything in the ice.

    This is our core. I’m working on this one. So I’m loading the next Antarctic core onto the melter now. It’s not the easiest of jobs, it’s a little bit fiddly.

    It melts the ice core6 layer by layer, back through time, and as the water is produced, it is pumped by these pumps into these various tubes, and this allows us to do analysis on all sorts of things that are contained in these ice cores.

    Some of the elements7 that we measure, we measure in parts per quadrillion, and to visualise that or to get a feel for what that actually means is we are looking for a second in 33 million years. We see traces of nuclear bomb testing. So we are looking for dust as an indicator8 of wind strength. We are looking for properties of the water that tell us about the temperature, where this air mass9 may have come from that precipitated the snow. You could almost say we are taking the DNA10 of the atmosphere.

    In the ice cores, there are little bubbles, and those bubbles contain a real sample of the atmosphere through time. We can release that air and measure the greenhouse gases11, and so by studying how much of these various components are in the ice, we get a feel for what climate12 was like at the time when the snow fell.

    If you take all these records together from across the continent13, there are some very strong messages that stand out, and these are really that the last 50–150 years were vastly different from the last 1,000 or 10,000 years. For example, we look at the hydrogen14, oxygen15, the stable isotopes16 of water, which gives us a very good indication of temperature at the continent, and it has increased over the last 50 years or 150 years.

    So if we view something like CO2, it has remained at pretty much 280 ppm17 over the last 1,000 or 10,000 years. Right now, we are already 386 I think.

    We look at things like methyl sulfonate. This is produced by bacteria18 that lives in the sea ice, and therefore we measure their productivity in the ice cores, and it tells us sea ice has changed.

    If we look, for example, at certain chemistry in the ice core, for example, the marine elements from the ocean, we can see that these westerly winds that circumnavigate the Antarctic have intensified and came closer to Antarctica.

    If Antarctica is changing, it will have very fundamental consequences for the rest of the planet – like sea level, productivity of the oceans, the heat19 budget of the globe, zone tracks, wave patterns, things that we don’t even know yet how they will be impacted by these changes.

    Acknowledgements

    This video is an extract from Thin Ice – The Inside Story of Climate Science, a David Sington/Simon Lamb film.

    The full documentary film is available by emailing thiniceclimate@vuw.ac.nz. The link for streaming is available free of charge. The DVD is also available to New Zealand schools for $20 to cover costs.

    © Thin Ice/University of Waikato

    1. ice core: A core sample, typically removed from an ice sheet. Ice cores are long cylinders of ice recovered by drilling with a hollow bit. Ice cores contain information about past climates.
    2. temperature: A measure of the degree of hotness or coldness of an object or substance. Temperature is measured with a thermometer calibrated in one or more temperature scales. Kelvin scale temperature is a measure of the average energy of the molecules of a body.
    3. periodic table: The organisation of all known elements into groups with similar properties.
    4. atmosphere: 1. The layer of gas around the Earth. 2. (atm) A non-SI unit of pressure equivalent to 101.325 kPa.
    5. continent: In geology, any of the main continuous expanses of continental crust on the Earth. Africa, Antarctica, Asia, Australia, Europe, North America and South America are recognised as continents, but this is based on historical and cultural attributes rather than geological attributes.
    6. ice core: A core sample, typically removed from an ice sheet. Ice cores are long cylinders of ice recovered by drilling with a hollow bit. Ice cores contain information about past climates.
    7. element: A substance made of atoms that all have the same atomic number. Elements cannot be split into simpler substances using normal chemical methods.
    8. indicator: Something that indicates the state or level of something. In ecology, a species that indicates the existence of certain environmental conditions. In chemistry, a substance that indicates the presence (or absence) of a chemical species at a specific concentration.
    9. mass: The amount of matter an object has, measured in kilograms.
    10. DNA: Deoxyribonucleic acid (DNA) is a molecule that contains the instructions needed for an organism to develop and function. These instructions are stored as a code made up of four chemical bases: adenine (A), guanine (G), cytosine (C) and thymine (T).
    11. greenhouse gases: A natural or manmade gas that traps heat in the Earth's atmosphere and contributes to the greenhouse effect. The main greenhouse gases are water vapour, carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), ozone and industrial gases such as chlorofluorocarbons (CFCs). These gases in the Earth's atmosphere trap warmth from the Sun and make life possible. An overabundance of greenhouse gases leads to a rise in global temperatures – known as the greenhouse effect.
    12. climate: The weather conditions of an area averaged over a series of years, usually 30 or more.
    13. continent: In geology, any of the main continuous expanses of continental crust on the Earth. Africa, Antarctica, Asia, Australia, Europe, North America and South America are recognised as continents, but this is based on historical and cultural attributes rather than geological attributes.
    14. hydrogen: First element on the periodic table –­ symbol H, with the atomic number of 1, meaning that it has a single proton in its nucleus.
    15. oxygen: A non-metal – symbol O, atomic number 8. Oxygen is a gas found in the air. It is needed for aerobic cellular respiration in cells.
    16. isotope: Different forms of atoms of the same element. Within the nucleus, there is the same number of protons but a different number of neutrons, giving each isotope a different atomic mass.
    17. parts per million: A commonly used term to describe a very small amount of something: one part in one million parts. For example, 32 seconds out of a year is 1 part per million (ppm). In chemistry, a unit of measure for very small concentrations (dilutions). This can be expressed as milligrams per litre (mg/L).
    18. bacteria: (Singular: bacterium) Single-celled microorganisms that have no nucleus.
    19. heat energy (heat): Heat energy: the transfer of energy in materials from the random movement of the particles in that material. The greater the random movement of particles the more heat energy the material has. Temperature is a measure of the heat energy of a material.
      Heat: the flow of energy from a warm object to a cooler object.
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      ice core

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      2. A core sample, typically removed from an ice sheet. Ice cores are long cylinders of ice recovered by drilling with a hollow bit. Ice cores contain information about past climates.

      atmosphere

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      3. 1. The layer of gas around the Earth.

      2. (atm) A non-SI unit of pressure equivalent to 101.325 kPa.

      indicator

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      4. Something that indicates the state or level of something. In ecology, a species that indicates the existence of certain environmental conditions. In chemistry, a substance that indicates the presence (or absence) of a chemical species at a specific concentration.

      greenhouse gases

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      5. A natural or manmade gas that traps heat in the Earth's atmosphere and contributes to the greenhouse effect. The main greenhouse gases are water vapour, carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), ozone and industrial gases such as chlorofluorocarbons (CFCs). These gases in the Earth's atmosphere trap warmth from the Sun and make life possible. An overabundance of greenhouse gases leads to a rise in global temperatures – known as the greenhouse effect.

      oxygen

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      6. A non-metal – symbol O, atomic number 8. Oxygen is a gas found in the air. It is needed for aerobic cellular respiration in cells.

      bacteria

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      7. (Singular: bacterium) Single-celled microorganisms that have no nucleus.

      temperature

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      8. A measure of the degree of hotness or coldness of an object or substance. Temperature is measured with a thermometer calibrated in one or more temperature scales. Kelvin scale temperature is a measure of the average energy of the molecules of a body.

      continent

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      9. In geology, any of the main continuous expanses of continental crust on the Earth. Africa, Antarctica, Asia, Australia, Europe, North America and South America are recognised as continents, but this is based on historical and cultural attributes rather than geological attributes.

      mass

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      10. The amount of matter an object has, measured in kilograms.

      climate

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      11. The weather conditions of an area averaged over a series of years, usually 30 or more.

      isotope

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      12. Different forms of atoms of the same element. Within the nucleus, there is the same number of protons but a different number of neutrons, giving each isotope a different atomic mass.

      heat energy (heat)

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      13. Heat energy: the transfer of energy in materials from the random movement of the particles in that material. The greater the random movement of particles the more heat energy the material has. Temperature is a measure of the heat energy of a material.
      Heat: the flow of energy from a warm object to a cooler object.

      periodic table

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      14. The organisation of all known elements into groups with similar properties.

      element

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      15. A substance made of atoms that all have the same atomic number. Elements cannot be split into simpler substances using normal chemical methods.

      DNA

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      16. Deoxyribonucleic acid (DNA) is a molecule that contains the instructions needed for an organism to develop and function. These instructions are stored as a code made up of four chemical bases: adenine (A), guanine (G), cytosine (C) and thymine (T).

      hydrogen

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      17. First element on the periodic table –­ symbol H, with the atomic number of 1, meaning that it has a single proton in its nucleus.

      parts per million

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      18. A commonly used term to describe a very small amount of something: one part in one million parts. For example, 32 seconds out of a year is 1 part per million (ppm).

      In chemistry, a unit of measure for very small concentrations (dilutions). This can be expressed as milligrams per litre (mg/L).

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