UN ozone experts to meet in Central Otago
Media Release 20 February 2006
United Nations ozone experts to meet in Central Otago
A high-powered scientific panel will be meeting in Alexandra later this week to consider the environmental effects of ozone depletion.
The National Institute of Water & Atmospheric Research (NIWA) is hosting the meeting of the United Nations Environment Programme panel between 24 February and 4 March.
The panel is made up experts from Europe, Scandinavia, North and South America, Africa, and Asia. About 24 members of the panel are expected to attend the New Zealand meeting, where they will produce a draft report on the environmental effects of ozone depletion and its interactions with climate change. That report will be reviewed by other experts before being presented in November to the parties which have signed the Montreal Protocol on ozone-depleting substances.
The only New Zealander on the panel is Dr Richard McKenzie who works at NIWA’s atmospheric research station near the tiny Central Otago settlement of Lauder.
‘Our previous report noted that at mid latitudes the ozone layer appears to be starting to recover,’ says Dr McKenzie, ‘however a full recovery would not be expected until the middle of the century at the earliest and the springtime ozone hole over Antarctica is predicted to recur for several decades.’ Panel co-chair Janet Borman noted that ‘rates of skin cancers amongst light-skinned people are expected to continue to rise rapidly’. There’s also growing interest in how to ensure some at-risk groups safely get enough UV in the winter, to avoid vitamin D deficiency.
NIWA has hosted two previous meetings of the panel: in Queenstown, 1996, and Wellington, 2002. Nonetheless, it is still rare for such a distinguished group of scientists to gather in New Zealand, let alone in the Central Otago district. The district’s mayor, Malcolm MacPherson, is hosting a civic reception for the visitors on Saturday 25 February.
The panel will be looking at the effects of ozone depletion on:
- UV radiation, including early indications from the southern hemisphere of a levelling off or even decrease in UV radiation at the Earth’s surface since the ‘turnaround’ in ozone.
- Health, including the need for eye protection from UV (even when it is not sunny and regardless of skin colour), the incidence of skin cancers, and vitamin D insufficiency and deficiency amongst some groups.
- Terrestrial Ecosystems, including suggestions that increasing nitrogen supply to plants may result in additional sensitivity to UV-B radiation, which has implications for agricultural practices.
- Aquatic Ecosystems. The panel’s previous (2005) report warned: ‘It is likely that we are consistently underestimating the ecological impacts of climate change and enhanced UV-B radiation by failing to consider the complex interplay of environmental variables and their impact on organisms.’
- Biogeochemical Cycles, that is, the interactions and feedback loops between climate change, UV radiation, and the production and absorption of various chemicals. For example, UV-B accelerates the production of carbon dioxide (the most significant greenhouse gas) from organic matter that runs off the land into freshwaters and the ocean.
- Air quality, including the global warming potential of some chemicals proposed as substitutes for the ozone-depleting chemicals, chloro-hydrofluorocarbons (CHFCs).
- Materials, including how higher temperatures and UV radiation might affect plastics.
The Montreal Protocol on Substances That Deplete the Ozone Layer is an international treaty providing for the gradual phase-out of the production of ozone-depleting chemicals. There are a few exceptions for essential uses such as asthma inhalers. It came into force on 1 January 1989 & there have been five subsequent revisions.
The full text can be found at:
The ozone ‘hole’ is an area over Antarctica where stratospheric ozone is very thin. It breaks up in late spring or early summer, and ozone depleted air then mixes with the surrounding air diluting the amount of ozone in mid-latitudes including New Zealand over the summer. The prerequisites for the creation of the ozone ‘hole’ are:
- extremely cold temperatures creating a polar ‘vortex’ (a strong wind circling around the pole in the middle to lower stratosphere) which isolates the air over Antarctica;
- this very cold air is necessary for the formation of polar stratospheric clouds;
- ozone depleting chemicals react on the surface of polar stratospheric clouds;
- as temperatures warm up in spring, further chemical reactions are triggered which prompt the rapid destruction of ozone over Antarctica.
For information on the size of the 2005 hole compared with previous years, visit this NASA site: http://toms.gsfc.nasa.gov/eptoms/dataqual/ozone_v8.html
atmospheric research at Lauder, includes
- The best instrumented site in the southern hemisphere for stratospheric research to understand the causes and effects of ozone depletion.
- One of 19 ‘primary’ fully-instrumented sites worldwide in the global Network for the Detection of Stratospheric Change. The only fully-instrumented site in the southern hemisphere mid-latitudes.
- Lauder scientists track the development and break up of the Antarctic ozone ‘hole’ each year using satellite data and ground-based measurements from their instruments at the Antarctica NZ site at Arrival Heights, Antarctica.
- One of 4 ‘charter’ sites in the world for the global Total Carbon Column Observing Network. The other sites are in the US, Australia, and Germany.
- This involves recently developed techniques to measure the amount of various greenhouse gases in a ‘column’ through the entire atmosphere. Both the US and Japan currently have plans for satellites dedicated to measurement of carbon columns from space, and the network will be vital to validate the results.
- This research will help scientists around the world better measure the amount of these gases entering and leaving the atmosphere. And that, in turn, gets us closer to predicting the timing and severity of climate change.
Links between ozone & climate change
- The ozone layer and climate change interact in complicated ways. For example, as greenhouse gases trap more heat close to the Earth’s surface, the stratosphere (at 10-50km above the ground) will cool down. This favours the production of more ‘polar stratospheric clouds’, which deplete ozone at the poles. At the same time, however, a cooler stratosphere will slow down the chemical reactions which destroy ozone away from the poles.
- To investigate the likely effects of the many links, NIWA runs a coupled chemistry-climate model on its Cray T3E supercomputer (at Greta Point, Wellington). This work is done in close collaboration with the UK Met Office and the NOAA Geophysical Fluid Dynamics Laboratory (USA).
Ultraviolet Radiation (UV)
- The risk of UV damage is relatively high in New Zealand. UV intensities are about 50% greater in NZ than in comparable latitudes in Europe, and 40% greater than in comparable locations in North America. This is because of our relatively clean air, lower ozone levels, and close proximity to the sun in summer.
- NIWA-developed systems for measuring UV operate in the USA (Hawaii and Boulder), Australia (Alice Springs and Darwin), and Japan (Tokyo).