NOVEMBER 1998

OZONE DEPLETION


YET ANOTHER RECORD OZONE HOLE
According to recent data issued by NASA and the US National Oceanic and Atmospheric Administration (NOAA), the size of this year's ozone hole over the Antarctic has yet again beaten all previous records.

Readers of Atmospheric Issues will be familiar with the annual reoccurrence of the Antarctic ozone hole every September to October (during the Southern Hemisphere springtime). Ozone depletion accelerates during these months due to a combination of low upper atmospheric temperatures, isolated atmospheric airflow, and the return of sunlight after the winter.

This year's hole measured 27.3 million km2 on 19 September, beating the previous record by 5%, set two years ago. The most widely accepted explanation for this year's record depletion is colder than average upper atmospheric temperatures, which allow the formation of polar stratospheric clouds (PSCs), conducive to ozone destruction. The cooler upper atmospheric temperatures may be a consequence of lower atmosphere and surface warming, as a result of heat trapping by greenhouse gases.

Although the largest ozone hole ever recorded, it is not quite the "deepest", with minimum ozone concentrations slightly above the record lows set in 1994.

Source: Global Environmental Change Report, 9 October 1998, Vol. X, No. 19.



CLIMATE CHANGE


SUB-SURFACE TEMPERATURE RECORDS CONFIRM GLOBAL WARMING....
According to analyses of sub-surface temperatures from a worldwide network of boreholes, the Earth's average temperature has increased by about 1oC over the last 5 centuries, with as much as 50% of the warming occurring during the last years.

Reporting in the journal Science (9 October, vol. 282), researchers at the University of Michigan (USA) collected data from over 350 boreholes from around the world, including eastern North America, central Europe, southern Africa and Australia. Finding the warming trend, the scientists noted that such observations are largely consistent with other reconstructions of historic temperatures, such as tree ring and ice core analyses (see next story), providing independent confirmation of the unusual warming of the 20th century.

Source: Global Environmental Change Report, 9 October 1998, Vol. X, No. 19.


....AS DO TREE RINGS, ICE CORES AND CORALS
Further confirmation of climatic warming has been demonstrated by an analysis of tree rings, ice cores and corals by climate scientists at the University of East Anglia, Norwich.

Globally averaging reconstructed temperatures from 17 different sets of data (10 from the northern hemisphere and 10 from the southern hemisphere), the 20th century was found to be the warmest of the last 10 centuries, whilst the 1981-1990 period was found to be the warmest decade. 1468, 1469 and 1898 were the warmest years, although the analysis only considered temperatures up to 1991.

Source: Global Environmental Change Report, 25 September 1998, Vol. X, No. 18.


CLIMATE-FRIENDLY ENERGY SUPPLY
Amerada Hess, the leading gas and oil producer in the UK, has launched the UK's first environmental tariff for domestic gas supply. Under the scheme household customers pay a small surcharge to the Carbon Storage Trust, a non-profit-making organisation engaged in activities that offset man-made emissions of carbon dioxide. Amerada Hess also makes a contributory payment for each customer who signs up for the new tariff.

Source: Global Environmental Change Report, 9 October 1998, Vol. X, No. 19.


CLIMATE CHANGE AFFECTS WATER QUALITY
River water quality in England and Wales may be declining as a result of climate change, according to the Environment Agency. Although water quality improved between 1990 and 1996 as a result of environmental improvements being made by the water industry, water quality has deteriorated since then.

The largest decline has been witnessed in southeast England, which has experienced particularly low rainfall during much of the 1990s. According to the Environment Agency, this suggests that longer-term climatic changes, through shifts in the weather, are having an effect on river water quality.

Source: Global Environmental Change Report, 11 September 1998, Vol. X, No. 17.


CATALYTIC CONVERTERS MAY ENHANCE GLOBAL WARMING
Data from the US Environmental Protection Agency indicate that the growing use of catalytic converters in cars to reduce local air pollution from road transport may be enhancing the prospects for global warming.

Catalytic converters remove the exhaust pollutants nitrogen dioxide (NO2) and carbon monoxide (CO), but release nitrous oxide (N2O), a potent greenhouse gas, as a by-product. According to the US EPA, emissions of nitrous oxide rose by almost half in the USA over period 1990 to 1996.

A similar increase in nitrous oxide emissions is expected to occur in Europe, as legislation introduced in the early 1990s to curb emissions of nitrogen dioxide and carbon monoxide take effect.

Source: Air Quality Management (September 1998).



AIR QUALITY


LONDON UNDERGROUND IS HIGHLY POLLUTED
Researchers at the University of Middlesex have demonstrated that the London Underground system may a rather unhealthy place to be. According to the data, passengers are being exposed to concentrations of particulates (PM10) 22 times the level of the Department of the Environment, Transport & the Region's health standard of 50µgm-3,.

Sources of the particulates may include vaporised metal from sparks, and abrasion of brake blocks. 70% of the particulates were found to be composed of iron oxide.

In addition to PM10 pollution, the Underground also experiences higher than normal concentrations of radon, and ozone, produced by the trains' electric motors. Although monitoring conducted independently by London Transport has to date failed to find any link between Underground pollution and health, they accept that it is not entirely possible to rule out that such a link may exist.

Source: Air Quality Management (October 1998).


OZONE IMPLICATED IN HOSPIAL ADMISSIONS
Results of a cross-European study of the short-term effects of air pollution on hospital admissions of respiratory diseases, published in the Archives of Environmental Health (vol. 53, no. 1), reveal that ozone is the chief air pollutant responsible for emergency hospital admissions.

The research was conducted in London, Paris, Milan, Amsterdam and Rotterdam. Given the difference in climatic conditions experienced by each city, the researchers suggest that the link between ozone pollution and respiratory disease is unlikely to be a reflection of weather conditions.

Source: Air Quality Management (October 1998).


POLLUTION MAKES WEEKENDS WETTER
It seems that weekends really are wetter - at least in the United States. According to climate scientists at Arizona State University reporting in the journal Nature (vol. 394), Saturdays between 1979 and 1995 on the east coast of the USA were 22% wetter than Mondays.

According to the authors, nothing in nature operates on a weekly timescale. Consequently, the 7-day rainfall cycle must be the result of some man-made factor, believed to be air pollution. Indeed, atmospheric concentrations of air pollutants are known to increase towards the end of the working week, largely as a consequence of traffic exhaust emissions, reaching a maximum on Fridays and Saturdays before subsiding over the weekend. It is possible that particulate pollution may be inducing raincloud formation by an enhanced "seeding" mechanism.

Clouds form by water vapour condensing around microscopic particulates in the atmosphere, a process known as seeding. Theoretically, if additional man-made particulates are added to the atmosphere, the rate of cloud seeding should increase.

The weekly cycle of air pollution apparently also affects the strength of storms. Weaker storms generally occur at weekends, supposedly because the enhanced cloud formation dissipates some of the storm's energy.

Although a link between air pollution and rainfall has not been demonstrated in the UK, the researchers believe that a general increase of rainfall on this side of the Atlantic may be the result of air pollution in the eastern USA.

Source: Air Quality Management (September 1998).



ENERGY


NEW ROUND OF REWNEWABLE ENERGY PROJECTS
A new round of renewable energy projects for the UK, under the 5th Non-Fossil Fuel Obligation (NFFO-5), were announced in September by UK Energy Minister John Battle.

The Non-Fossil Fuel Obligation, introduced by the previous Government, obliges electricity suppliers to purchase energy produced from renewable sources. NFFO-5 represents the largest round of renewable energy projects to date, with a total of 261, including landfill gas, energy from waste and wind power, producing a total energy capacity of 1,177 megawatts (MW). This would bring renewables' share of the electricity market up to about 5%.

In an effort to promote the cause of renewable energy further, the Energy Minister has also announced plans to develop 8 demonstration offshore wind farms.

Source: ENDS Report 284, September 1998.


PHASING OUT FOSSIL FUELS
The UK Royal Commission on Environmental Pollution (RCEP) is assessing the implications of reducing or phasing out the use of fossil fuels in a new study.

Whilst the emphasis will be on identifying the role of renewable energy, the Commission will also be considering the potential for nuclear power. Currently, the UK Government is committed to a renewables energy supply of 10% of the total UK supply by 2010. Given the legislative, economic, and social difficulties associated with the replacement of conventional fossil-fuel power generation, a substantial reduction in carbon dioxide emissions should not be expected until the middle of the next century at the earliest.

Source: Air Quality Management (September 1998).



TRANSPORT


EUROPEAN CO2 EMISSIONS FROM CARS TO BE CUT BY 25%
Emissions of carbon dioxide (CO2), a chief greenhouse gas, are to be reduced by 25% by 2008 to 2012, from the exhaust emissions of new cars, under a new ruling by the Council of European environment ministers. This follows the voluntary agreement between the Association of European Car Manufactures and the European Commission to reduce average new car emissions of carbon dioxide to 120g/km by 2010.

Source: Local Transport Today, no. 248, 8th October.


CENTRAL LONDON TO BECOME A LOW EMISSION ZONE
The City of Westminster in London is to become a local air quality management area, following the 1995 Environment Act and research to be reported assessing the effects of restricting access to zero and low emission vehicles.

The study into traffic restrictions is expected to be available by the middle of next year. Westminster could become a "Low Emission Zone by mid-2000.

Source: Local Transport Today, no. 246, 10th September.