The ozone layer over New Zealand is thinner. Unfortunately, due to decades of man-made gas emissions, the ozone layer over New Zealand has continuously thinned. The ozone layer is like the Earth's personal sun protectant. The ozone layer's role is to absorb the harmful UV rays that are sent from the sun.
annual average thickness of the ozone layer over New Zealand was 308DU, which is slightly thicker than the global average of 300DU (Liley & Mckenzie, 2007).
The stratospheric ozone layer absorbs the biologically damaging wavelengths of ultraviolet (UV) rays but in the 1970s, Australia's ozone layer was severely thinned as a consequence of heavy use of ozone-depleting, substances such as chloroflurocarbons (CFCs) and hydro-chloroflurocarbons (HCFCs).
Chlorine and bromine derived from human-produced compounds are released from reactions on high-altitude polar clouds. The chemical reactions then begin to deplete the ozone layer as the sun rises at the end of the winter in the Southern Hemisphere, with the strongest depletion occurring above Antarctica.
The ozone hole does not have a large effect on the concentration of ozone over New Zealand. However, when the ozone hole breaks up in spring, it can send 'plumes' of ozone-depleted air over New Zealand. Reporting on the state of the ozone hole helps us understand the state of ozone concentrations globally.
At mid-latitudes, such as New Zealand, it is thickest during spring and thinnest during autumn. This means the ozone layer over New Zealand thins during summer, providing less protection from UV sunlight when we are closest to the sun and the sun is highest in the sky.
New Zealand's rather cool and temperate temperatures can easily hide the harmful effects of the sun. Yet in any season and any weather, the New Zealand sun can burn. Many people say they get more sunburned in New Zealand than anywhere else in the world, even Australia!
More about ozone layer depletion
This includes a five to nine per cent depletion over Australia since the 1960s, which has increased the risk that Australians already face from over-exposure to UV radiation resulting from our outdoor lifestyle.
The ozone layer is thinnest near the poles. In the 1970s, people all over the world started realizing the ozone layer was getting thinner and that this was a bad thing. Many governments and businesses agreed that some chemicals, like aerosol cans, should be outlawed.
Ozone depletion and climate change are linked in a number of ways, but ozone depletion is not a major cause of climate change. Atmospheric ozone has two effects on the temperature balance of the Earth. It absorbs solar ultraviolet radiation, which heats the stratosphere.
Australia's unusually harsh sunshine results mainly from its location in the Southern Hemisphere. The elliptical orbit of the Earth places the Southern Hemisphere closer to the sun during its summer months than the Northern Hemisphere during its summer.
During summer, the Earth's orbit brings Australia closer to the sun (as compared to Europe during its summer), resulting in an additional 7% solar UV intensity. Coupled with our clearer atmospheric conditions, this means that Australians are exposed to up to 15% more UV than Europeans.
Ozone depletion has been most severe over Antarctica because it provides the unique temperature and chemical conditions for effective ozone destruction by halogen gases.
Under normal circumstances, the ozone layer is thickest over the poles and thinnest around the equator.
The thinning is most pronounced in the polar regions, especially over Antarctica. Ozone depletion is a major environmental problem because it increases the amount of ultraviolet (UV) radiation that reaches Earth's surface, which increases the rate of skin cancer, eye cataracts, and genetic and immune system damage.
This is because seasonal changes in both sunlight and ozone transport are smaller in the tropics than in the polar regions. Natural variations.
Ozone Layer Hole is Healing, But Australian Wildfires Threaten Progress. While the ozone layer hole is healing and on the path to recovery by 2060, currently measuring about 7.6 million square miles, wildfire smoke from Australia's Black Summer has destroyed 1% of the ozone layer, a recent assessment found.
As the ozone hole over the south pole breaks up in spring, pockets of ozone depleted air drift across Tasmania, southern Victoria and the southern part of New Zealand's south island.
In the final quarter of 2022, scientists from NASA and the National Oceanic and Atmospheric Administration (NOAA), reported that the hole in the ozone layer is continuing to shrink. The hole lies above Antarctica and between 7 September and 13 October, 2022, it spanned an average area of 23.2 million square kilometres.
New Zealand has a maritime climate, which means that its weather is largely affected by ocean conditions, while Australia has a continental climate and is generally more self-regulating when it comes to weather conditions.
In terms of energy, the sun is stronger in Australia due to it being closer to the equator. But in terms of UV light which causes sunburn, it is stronger in New Zealand due to a thinner ozone layer, and less pollution (clearer air).
New Zealand has naturally high UV levels compared with similar latitudes. For example, our peak UV levels can be 40 percent higher than peak UV levels in similar North American latitudes (McKenzie et al, 2006).
As general guide, the Cancer Society of NZ recommends the use of broad-spectrum, SPF30+ sunscreen. Broad-spectrum sunscreen gives extra protection because it filters out both UVA and UVB rays. UVA causes ageing of the skin and long-term damage.
In New Zealand, its maximum summer value is generally about 12, but it can exceed 13 in the far North. In winter it reaches peak values of 1 or 2. Values of 10 or more should be considered as "extreme". At high altitude tropical sites (eg Mauna Loa Observatory, Hawaii), the UV Index can exceed 20.