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Our Changing World for Thursday 30 May 2013

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Carbon Dioxide Levels reach 400ppm

Earlier this month, the concentration of carbon dioxide in the atmosphere has reached 400ppm for the first time in human history. The last time this happened was around three million years ago, during a geological period known as the Pliocene. This was a warmer time in Earth’s history, with sea levels up to 20 metres higher than today and average global temperatures two to three degrees above today’s.

An international team of geologists and palaeo-climate scientists has studied this period during the ANDRILL project by drilling into the sediment below Antarctica’s Ross Ice Shelf and analysing the climate data from the 1137m core. The director of Victoria University’s Antarctic Research Centre, Tim Naish, led ANDRILL’s first drilling season. In this interview, he describes what the Pliocene world looked like and explains why this geological window is often used as an analogue for the future.

ANDRILL and related palaeo-climate research projects have featured on Our Changing World in the past. You can find out more about ANDRILL and the ice-core RICE project.

Generation Zero

Campaigning for electric transport options: electric bike enthusiast Jace Hobbs, at left, and Generation Zero members Stephanie Gregor and Louis Chambers (image: V Meduna)

Generation Zero is a group of young people who consider climate change as the biggest challenge for their generation. Their aim is to reduce reliance on fossil fuels and to transform New Zealand into a zero-carbon economy, in their lifetime. This year, transport is the focus of the group's campaigns, including the 50/50 project which calls for a greater share of transport spending to be allocated to public transport and cycleways, and the 100% Possible campaign to move beyond fossil fuels.

New Possum Trap Lure

Experts from different institutions in New Zealand agree that if we are to make progress towards a predator-free New Zealand we need to develop better toxins and improve trapping techniques.

One group working towards these goals is the Wildlife Ecology Group at Landcare Research, and Alison Ballance heads to a forestry block in McQueens Valley on the south side of Banks Peninsula to meet research technician Samanatha Brown who’s field-testing a possible new possum lure. The lure is urine from female possums that are in oestrus, and previous pen trails showed that both male and female possums were highly attracted to it. If field trials show it has a high success rate then the idea will be to identify active compounds in the urine and develop a synthetic version.

Part of the field trial also involves measuring how possums interact with traps: possums are tagged with radio collars that include RFID (radio frequency identification) tags – when the possum approaches a trap the RFID tag sends out a signal that can be picked up on an array of readers placed at different distances from the trap, to record how close each individual animal gets to the trap and how long it spends there.

Sam Brown and John Williams next to a possum trap that is being monitored to see if urine from a female possum in oestrus is an effective lure

Samantha Brown and John Williamson next to part of a field trial to see if urine from a female possum in oestrus is an attractive lure. The trap is buried in the ground at the base of the tree, flour and icing sugar is used asa normal lure and the additional trial lure is contained in the performated white container. The black plastic device contains a scanner that can read RFID devices carried by radio-collared possums (image: A. Ballance)

Pharmacogenomics

Pharmacogenomics is the study of how genes affect a person’s response to drugs. It may one day lead to personalised medicine tailored for our individual genetic make-up, but it’s still early days - and as Martin Kennedy, Director of the Carney Centre for Pharmacogenomics at the University of Otago, Christchurch, tells Alison Ballance we’re only just beginning to understand how differences in our DNA and our individual genetic make-up impact on both disease and its treatment, and in the recognition of how many genes may be involved in a single disease.

Alison also talks with summer student Leon Smyth who was looking at the effect of the drug-metabolising enzyme CYP2C19 on the response of individuals to the anti-clotting medication Clopidogrel, and PhD student Sarah Jodczyk who is investigating differences in chromosome telomere length between people who have been exposed to different kinds and amounts of stress.