Some atmospheric issues have been solved effectively as
a result of a variety of mechanisms and where successful
action has been taken, the benefits far exceed the costs.
Significant progress has, for example, been made in
reaching the internationally agreed goal of the Montreal
Protocol to protect the stratospheric ozone (ozone in
the upper atmosphere) layer. A drastic reduction in both
the production and use of ozone-depleting substances
(ODS) has been achieved, resulting in a 31 per cent
improvement in ODS indicators at mid latitudes since
1994, and the predicted avoidance of 22 million cases of
cataract for people born between 1985 and 2100 in the
United States of America alone.
For other issues, such as the reduction of indoor and
outdoor PM and emissions of sulphur and nitrogen
compounds, progress has been mixed. Tropospheric
ozone (ozone in the lower atmosphere) remains a
significant problem and is proving difficult to address.In parts of Africa, Asia and Latin America, where
urban PM levels remain far in excess of international
guidelines, the concern is high. Similarly, the dust-haze
phenomenon in the Middle East is of concern. Improved
public information on local air quality could contribute to
raising awareness of this issue.
The internationally agreed goal of avoiding the adverse
effect of climate change is presenting the global
community with one of its most serious challenges
(Figure 2) that is threatening overall development
goals. As progress in reducing the carbon intensity of
consumption and production is being outstripped by
increased levels of consumption, reaching the climate
goal under the United Nations Framework Convention on
Climate Change (UNFCCC) of reducing global greenhouse
gas (GHG) emissions so as to hold the increase in global
average temperature below 2° C above pre-industrial
levels will require not only the fulfilment of current
pledges but also transformative change towards a lowcarbon
global economy.
In addition, progress is necessary on preparing and
implementing national plans of action on climate change,
including nationally appropriate mitigation action and
national adaptation plans of action. Complementary action
to address short-lived climate forcers – black carbon,
methane and tropospheric ozone, which are air pollutants
that also warm the planet – can cost-effectively reduce
the rate of temperature increase in the near term while
reducing risks to human health and food production.