The concern about the destruction of the ozone layer by chlorofluorocarbons (CFCs) led to the signing of the Vienna Convention for the Protection of the Ozone Layer in 1985 (see Box 5.8). This was an international agreement by nations to take some action to stop atmospheric ozone depletion, but the nature of the action was not spelled out. The Vienna Convention was given teeth with the signing of the Montreal Protocol on Substances that Deplete the Ozone Layer in 1987. The Protocol set timetables for the phase-out of specific chemicals. As increasing numbers of synthetic chemicals have been implicated in ozone depletion, and as the science of the destruction process has become better understood, the Protocol has been amended twice (London in 1990, and Copenhagen in 1992), and adjusted once (Vienna in 1995). These amendments and adjustments have added new chemicals to the list and tightened the phase-out timetables (see Boxes 5.8 and 5.9). (Amendments to the Protocol must be ratified by governments to take effect; adjustments do not require ratification.)
A ban on the production of various CFCs and halons began in January 1996, as required by the Montreal Protocol, and the consumption of CFCs and halons is now dropping globally. There are indications that the ozone-destroying potential of atmospheric chlorine and bromine peaked in the troposphere in 1994.
Provided countries abide by the provisions of the Montreal Protocol, the chlorine/bromine destruction potential should peak in the stratosphere between 1997 and 1999. The ozone layer would then begin to heal slowly, reaching pre-ozone-hole levels by about the year 2050 (Hofmann, 1996) (see Figure 5.18).
Textual description of figure 5.25
New Zealand's levels of ozone-depleting substances (CFC-12, CFC-11 and CFC-113) have decreased between 1986 and 1996. Levels have reduced particularly since the Montreal Protocol was signed in 1987.
Source: Ministry for the Environment, unpublished data
Because New Zealand does not manufacture CFCs and halons, assessment of local use is based on import data. Figure 5.25 shows the amount of three ozone-depleting substances imported into New Zealand from 1986 to 1996, the phase-out completion year. The international phase-out timetables for ozone-depleting substances, and the staggered deadlines applying to New Zealand industries which use them, are shown in Box 5.9.
Parties to the Montreal Protocol must also monitor the manufacture or the importation of other ozone-depleting substances. These include hydrobromofluorocarbons (HBFCs), hydrochlorofluorocarbons (HCFCs), carbon tetrachloride, methyl bromide, and methyl chloroform (see Box 5.9). In addition, the non-ozone-depleting greenhouse gases, hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs), are monitored by the Ministry for the Environment.
Imports of HBFCs were banned in advance of the Montreal Protocol's requirements from 1 July 1992. Imports of hydrochlorofluorocarbons (HCFCs) were frozen at 75 percent of the permitted 1989 'base year' figure from 1 January 1996. (New Zealand capped its HCFC imports 25 percent lower than allowed under the Copenhagen Amendments to the Protocol because only about half the permitted amount was imported in 1994.) Government policy is that HCFCs must be phased out by 2015, 15 years ahead of the Montreal Protocol requirement.
Box 5.8: The Vienna Convention and the Montreal Protocol
The controversial theory put forward by Molina and Rowland (1974) that chlorofluorocarbons could be destroying the ozone layer was debated by scientists and challenged by industry. Nevertheless, it captured the public imagination, and for the next three years pressure built up in the United States and other countries for controls to be placed on the use of CFCs. During 1975 and 1976, the United Nations Environment Programme (UNEP) organised several conferences to discuss threats to the ozone layer. In May 1977 the United States announced that it would phase out the use of CFCs in aerosol spray cans. CFC consumption fell temporarily in the early 1980s, but lingering scientific uncertainty about the impact of CFCs on the ozone layer caused some people to cast doubt on the need to reduce their use. Consumption began rising again with other uses making up for the cuts produced by the aerosol bans.
Firmer evidence of CFCs' impact on ozone came from laboratory studies and computer models in 1980. It suggested that CFCs could pose a serious threat to human health and the well-being of the planet. The threat was answered in 1985 when concerned nations met to sign the Vienna Convention for the Protection of the Ozone Layer. The Vienna Convention simply obliged signatory nations to take "appropriate measures to protect human health and the environment against adverse effects resulting, or likely to result from human activities which modify, or are likely to modify the ozone layer." The measures, however, were not specified. CFCs were only mentioned towards the end of the annex to the treaty, where it was suggested that the chemicals should be monitored.
The first evidence that urgent action was required came in mid-1985 when Dr Joe Farman and colleagues from the British Antarctic Survey published a paper showing that there appeared to be a massive loss of ozone in the spring at the Halley Bay station (Farman etal., 1985). They had discovered what is now known as the Antarctic Ozone Hole (see Figures 5.15 and 5.16). On 16 September 1987, the Montreal Protocol was signed into being by representatives of 21 nations. The Protocol actually came into force on 1 January 1989, by which time 29 countries and the EEC had ratified it. It set the minimum requirement of freezing the consumption of five CFCs (CFCs11, 12, 113, 114, and 115) at 1986 levels by 1 July 1989, with a similar freeze on the consumption of three halons (Halons 1211, 1301, and 2402) to be achieved by 1 February 1992.
Since the Montreal Protocol came into force, the phase-out schedules have been tightened three times, first by the London Amendments in 1990, then by the Copenhagen Amendments in 1992, and most recently, by the Vienna Adjustments in 1995. The London Amendments added methyl chloroform, carbon tetrachloride, and ten other CFCs to the list of ozone-depleting substances. The Copenhagen Amendments added HCFCs, HBFCs, and methyl bromide to the list of chemicals in the phase-out schedules. They also required Protocol Parties to completely phase out their consumption of ozone-depleting substances (except HCFCs and methyl bromide) by 1 January 1996. The Vienna Adjustments added a phase-out schedule for methyl bromide and brought forward the phase-out schedule for HCFCs.
Box 5.9: Phase-out timetables for ozone-depleting substances
As a Party to the Montreal Protocol on Substances which Deplete the Ozone Layer, New Zealand has agreed to phase out all ozone-depleting substances no later than prescribed by the Protocol's timetables. Not all substances have to be phased out at the same rate, or have the same deadline, although all known ozone-depleting substances except HCFCs and methyl bromide, became prohibited imports from 1 January 1996. The phase-out schedules for New Zealand users are contained in the Ozone Layer Protection Act 1990. As no ozone-depleting substances are manufactured in New Zealand, the phase-out schedules relate to imports.
New Zealand phase-out schedules for imports of ozone-depleting substances
Halons: Imports banned from 3 October 1990.
HBFCs: Imports banned from 1 July 1992.
CFCs: (CFC phase-out schedules differ for each industry. CFC use in spray cans was banned in 1990, except for those required for medical purposes.)
National Overall Target:
75% phase-out by 1 January 1994.
100% phase-out by 1 January 1996.
Refrigeration andAir conditioning Industry:
55% phase-out by 1 July 1992.
70% phase-out by 1 January 1994.
90% phase-out by 1 January 1995.
100% phase-out by 1 January 1996.
Plastic Foam Making Industry:
55% phase-out by l July 1992.
100% phase-out by 1 January 1996.
General Solvent Use:
50% phase-out by 1 July 1993.
60% phase-out by 1 January 1994.
90% phase-out by 1 January 1995.
100% phase-out by 1 January 1996.
20% phase-out by 1 July 1990.
100% phase-out by 1 January 1996.
10% phase-out by 1 July 1993.
50% phase-out by 1 January 1994.
100% phase-out by 1 January 1996.
85% phase-out by 1 January 1994.
100% phase-out by 1 January 1996.
Methyl bromide: The Montreal Protocol requires that methyl bromide production and consumption be frozen at 1991 levels from 1 January 1995 and phased out in four steps by 2010. (Quarantine and pre-shipment (QPS) fumigation uses are exempt.) Consideration is also being given to a 'critical agricultural uses' exemption after 2010. This term was not defined at the Parties' conference in Vienna in 1995. A timetable for phasing out methyl bromide use in New Zealand is still under consideration.
HCFCs: Protocol requirement: freeze at 1989 'Base Year' figure from 1 January 1996. 100% phase-out by 1 January 2030.
New Zealand has agreed to a phase-out schedule faster than required for HCFCs under the Montreal Protocol. This caps consumption at 75% of the base year figure, and completely phases out consumption by 2015. (HCFC use in spray cans was banned in 1990, except those required for medical purposes.)
Responses to the threat of climate change
Unlike ozone depletion, which can only be dealt with by reducing emissions of the main pollutants, the threat of climate change can be dealt with in two ways: reducing emissions, or increasing the amount of carbon dioxide that is absorbed from the atmosphere.
Emissions can be reduced by either cutting back the activities that give rise to them (e.g. transport, industrial processes, agriculture), or developing new ways of doing things so that fewer emissions are produced (e.g. by using non-carbon energy sources, or more fuel-efficient technology).
Carbon absorption can be increased by boosting the amount of photosynthesis on Earth. Plants, algae and cyanobacteria absorb carbon dioxide whenever they trap the sun's energy through photosynthesis. The carbon is stored in their tissues and is only released back into the atmosphere when the organisms are oxidised, that is, when they are consumed by bacteria or fungi (i.e. decomposition), or animals (i.e. digestion), or fire (i.e. combustion). When trees are harvested for timber, some of the carbon remains in storage, as planks and other wood products, but the rest is released back into the atmosphere through these oxidative processes.
A mature forest is a carbon 'reservoir'. The trees have stopped growing and have locked up all the carbon they can. As a result, the amount of carbon dioxide absorbed by a mature forest is roughly equal to the amount lost through the natural oxidation of dead trees, fallen branches and leaves, and ingested wood and foliage. In contrast, an immature forest absorbs much more carbon than it releases because it is still growing. Young forests are therefore carbon 'sinks' that actively remove carbon dioxide from the atmosphere.
Globally, carbon reservoirs and sinks are declining through deforestation, but, in New Zealand, that trend has reversed. Most of our indigenous forests are mature carbon reservoirs that are legally protected from deforestation while many commercial exotic forests are young and fast-growing carbon sinks. This has led New Zealand to take a somewhat different approach from other countries in trying to meet its international obligations on greenhouse gas emissions.
The international movement to reduce the risk of climate change began in the early 1980s when the United Nations first recognised the increasing scientific concern about rising greenhouse gas emissions. In 1988 the UN General Assembly resolved to protect the global climate for present and future generations. As part of the response, the UN established the Intergovernmental Panel on Climate Change (IPCC) to provide the best possible scientific information and advice (see Box 5.5). That same year, New Zealand's Climate Change Programme was established, calling on all sectors of society to voluntarily make every effort to prevent detrimental effects on the world's climate.
Meanwhile, officials from UN member countries formed the Intergovernmental Negotiating Committee (INC) and began negotiating to get wide acceptance for a treaty that would commit each country to take steps to reduce the risk of climate change. In June 1992, at the United Nations Conference on the Environment and Development (UNCED or the 'Earth Summit') held in Rio de Janeiro, more than 150 nations signed the Framework Convention on Climate Change (FCCC) (see Box 5.10).
Box 5.10: The UN Framework Convention on Climate Change (FCCC)
The United Nations Framework Convention on Climate Change ( FCCC) is the international agreement negotiated under United Nations auspices to address concerns about climate change. It came into force on 21 March 1994. Its objective is:
... stabilisation of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. Such a level should be achieved within a time frame sufficient to allow ecosystems to adapt naturally to climate change, to ensure that food production is not threatened, and to enable economic development to proceed in a sustainable manner.
Among other things, the FCCC requires a commitment from developed countries to limit carbon dioxide and other human-induced greenhouse gas emissions not controlled by the Montreal Protocol, and to protect and enhance greenhouse gas sinks and reservoirs. Although the FCCC contains no legally binding targets or timetables, the general interpretation is that developed countries are committed under the convention to reducing their emissions to 1990 levels by the year 2000.
In April, 1995, at the first Conference of the Parties to the Convention, it was decided that existing commitments in the FCCC were inadequate to achieve the objective of avoiding dangerous human-induced interference with the climate system. The Parties established the Berlin Mandate process to negotiate strengthened commitments for developed countries, and to advance the existing commitments of developing countries, for the period beyond 2000. These negotiations are still in progress and are set to conclude in December 1997.
In July 1994, four months after the FCCC came into force, the New Zealand Government announced a set of measures to reduce carbon dioxide emissions. Like other developed countries (i.e. those in the OECD), New Zealand set itself the target of reducing emissions to 1990 levels by the year 2000 and maintaining them at that level from then on (Ministry for the Environment, 1994). However, while the other countries chose to reduce and stabilise their 'gross' emissions, New Zealand opted to reduce its 'net' emissions.
The difference is significant. 'Gross' emissions are the total amount of carbon dioxide that is released into the atmosphere from fossil fuel use and lime-burning industries such as cement manufacture. However, this does not include the extra carbon added by deforestation or the amount removed by forest growth. 'Net' emissions do take forest changes into account. As a result, 'net' emissions will be greater than 'gross' emissions wherever forest losses from harvesting, fires, pest damage and land clearance exceed a country's new forest growth. Conversely, 'net' emissions that will be lower than 'gross' emissions in countries whose forest growth exceeds deforestation. New Zealand's 'net' emissions are much lower than its 'gross' emissions so the 'net' target was adopted because it seemed much more achievable and less economically disruptive than a 'gross' target.
The spread of young commercial forests in New Zealand has been facilitated by a tax regime that allows businesses to deduct virtually all the costs of establishing and maintaining a forest in the year the expenditure is incurred. Of course, tax eventually has to be paid on the sale of the harvested trees but that is 25-35 years after planting. However, forest sinks cannot expand indefinitely, and ultimately emissions will have to be reduced to meet our international obligations. Recent assessments of forest plantings have reinforced this fact. In 1994, when new forest plantings reached a record high of 98,000 hectares, it seemed that they would continue at a rate of 100,000 hectares per year for the rest of the decade. But since then they have declined. New estimates by the Forest Research Institute now predict a planting rate of around 72,000 hectares per year until the year 2000, falling to 57,000 hectares per year for the next decade (Glass, 1996).
Of course, New Zealand's climate change policy recognised that forest growth alone would not offset all emissions and that something would also have to be done about gross emissions. Although it did not aim to reduce gross emissions, the policy did aim to slow down their growth by at least 20 percent. The key measures designed to achieve this were: energy sector reforms; an energy efficiency strategy managed by the Energy Efficiency and Conservation Authority (EECA); further development of renewable energy sources, also managed by EECA; use of the Resource Management Act; and a voluntary agreements scheme with industry. There were parallel policies to encourage increased carbon storage in plantation forests. It was expected that these measures in combination would ensure that New Zealand would achieve its CO2 policy objectives.
Also in the 1994 policy package was the warning that a low-level carbon charge would be introduced in December 1997 if it looked as though net carbon dioxide emissions would not stabilise at 1990 levels by the year 2000, or if the combination of measures for gross emissions did not achieve at least a 20 percent reduction in the growth in annual emissions for the period up to the year 2000. To encourage lower increases in carbon dioxide emissions, the Ministry of Commerce negotiated voluntary agreements with key industries and, by mid-1996, 21 agreements had been made.
To date, the only laws or regulations applying to greenhouse gas emissions are the controls on industrial air pollution imposed by local authorities under the Resource Management Act. Large emitters, such as companies engaged in energy-intensive industries like metal smelting, powdered milk manufacture and paper production, must receive an air discharge consent from their local authority. In one case, the Minister for the Environment decided to 'call in' a consent application for a new power station because it had the potential to increase New Zealand's CO2 emissions by 5 percent (see Box 5.11).
Box 5.11: The Stratford power station 'call-in'
In December 1993, the Minister for the Environment used the provisions of the Resource Management Act 1991 to 'call in' an application by the Electricity Corporation of New Zealand (ECNZ) to the Taranaki Regional Council for a consent to build a new gas-fired combined cycle power station at Stratford in Taranaki. The proposed station had the potential to add 5 percent to New Zealand's gross carbon dioxide emissions, and the Minister was concerned at both the domestic and international implications of the project in terms of greenhouse gas emissions and climate change policy.
A Board of Inquiry studied the proposal and recommended to the Minister that the consent be issued with a condition that the consent holder establish a carbon sink of sufficient size to absorb as much carbon as would be released from the plant during the term of the permit. This would have required the planting of about 3,500 hectares of new plantation forest for each year of the station's operation. The Minister granted the consent in March 1995 but made the condition more flexible so that, besides tree planting, CO2 mitigation measures could take the form of reductions in existing power generating emissions or cuts in carbon dioxide emissions in sectors outside electricity generation (i.e. through energy efficiency measures).
The Minister also reduced the mitigation requirement to apply only when emissions from the electricity sector exceeded the level reached just before the plant began operation. This rewarded the station owners for indirectly reducing CO2 emissions by replacing some older, less efficient, stations with the new plant. The proposed station and consent were subsequently sold to a consortium consisting of TransAlta, a Canadian utility, and two New Zealand companies, Mercury and Fletcher Challenge, the latter with extensive energy and forestry interests.
In August 1995, the New Zealand Government followed up its 1994 measures by establishing the Working Group on CO2 Policy. The Working Group was instructed to report back on several issues:
- whether the Resource Management Act is an appropriate mechanism for dealing with global pollutants such as carbon dioxide;
- the effect of strong economic growth on emission levels;
- whether New Zealand should continue to pursue the 'net' approach to carbon dioxide limitation; and,
- whether a carbon tax, or some other economic instrument (such as a tradeable emission permit system), is the best way to achieve the Government's carbon dioxide objectives.
The Minister for the Environment released the Working Group's report for public consultation on 20 June 1996 (Ministry for the Environment, 1996). The report concluded that New Zealand should continue with the 'net' approach in dealing with carbon dioxide. It also advocated the use of an 'economic instrument' to control carbon dioxide emissions, concluding that this approach would be more flexible and less costly than subsidies or regulations. In the four months following the report's release, submissions were invited from the public to assist in the further development of New Zealand's climate change policy (Ministry for the Environment, 1997b).
The need for further policy development is driven by the fact that New Zealand is not on track to achieve its current policy target of reducing 'net' carbon dioxide emissions to the 1990 level by the year 2000 and maintaining them at that level thereafter. In fact, 'net' carbon dioxide emissions in 1995 were nearly three times their 1990 level and are projected, in the absence of further measures, to remain well above the target level for the next three decades (see Figure 5.26).
Figure 5.26: Projected 'gross' and 'net' emissions of carbon dioxide in New Zealand
- These projections cover emissions from energy and industrial sources as well as those from forest harvesting, scrub clearance for new planting, wild fires and prescribed burning. They assume:
- no additional policy measures;
- GDP growth of 3 percent per year; and
- new forest plantings of 70,000 hectares per year up to 2005 AD, falling to 55,000 hectares per year thereafter.
- The 1994 policy target of reducing net emissions to 1990 levels by the year 2000 and maintaining them thereafter is currently being reassessed and different targets may be set for the period for the period beyond 2000.
Textual description of figure 5.26
Projected 'gross' and 'net' emissions of carbon dioxide in New Zealand indicate that the net emission level in 2000 will be more than twice the target level of 5 million tonnes.
Source: Ministry for the Environment (1997a)
Between 1990 and 1995 our yearly 'gross' carbon dioxide emissions increased by about 7 percent as economic growth increased. At the same time, the amount of carbon absorbed annually by plantation forests fell by 34 percent as more trees than expected were harvested and fewer planted. The increase in 'gross' emissions was in line with the policy (i.e. 20 percent lower than 'business as usual' projections). However, despite the slowed rate of increase, 'gross' emissions are projected to keep rising beyond the year 2000, driven by economic growth, while forest planting rates are expected to decline after that point. As a result, New Zealand's 'net' carbon dioxide emissions in and beyond the year 2000 will remain above the 1990 level even though the total size of the nation's carbon sink will keep expanding.
Under the current policy, New Zealand measures its performance in dealing with carbon dioxide by comparing the 'net' emissions in a given year with those in 1990, the chosen baseline year. However, single year comparisons can obscure the overall trend by omitting the intervening years. An alternative approach is to sum all the emissions over a given time period and compare the cumulative totals. When viewed in this way, the bigger picture can be seen more clearly and the cumulative contribution of forest growth can be better assessed.
Under a continuation of the current policy, for example, our cumulative 'net' emissions in 2020 would be around 375 million tonnes-two and a half times the 1990 level aggregated over the same period (see Figure 5.27). This confirms the trend seen in year-to-year comparisons but also shows that the 'net' emissions would be three times greater were it not for young forests absorbing most of our gross emissions. The cumulative view also shows why the 1990 'net' emission level cannot be met without an actual reduction in gross emissions. On current trends, 'gross' emissions will exceed a billion tonnes by the year 2020, which is 33 percent higher than they would have been if 'gross' emissions had been held at the 1990 level. Had 'gross' emissions been held at the 1990 level, forests would have absorbed 84 percent of them, pushing New Zealand's 'net' emissions below the 1990 level.
Figure 5.27: Cumulative carbon dioxide emissions in New Zealand 1991-2020
- Assumptions are the same as in Figure 5.26. The 1990 cumulative emissions are included here as a benchmark for comparison. They have been calculated by simply multiplying the emissions for that year over the three decades.
Textual description of figure 5.27
The cumulative carbon dioxide emissions in New Zealand over 1991-2020 are predicted to be 33% higher under current policy than they would be if the 1990 gross emission level had been held.
Source: Ministry for the Environment (1997b)
Table 5.6: Greenhouse gas emissions inventory 1990-95
| ||Annual emissions (1,000 tonnes) |
|Greenhouse Gases ||1990 ||1991 ||1992 ||1993 ||1994 ||1995 |
|CO2emissions ||25,476 ||26,007 ||27,954 ||27,276 ||27,326 ||27,368 |
|CO2absorption ||-20,569 ||-19,630 ||-18,173 ||-16,136 ||-14,708 ||-13,490 |
|Net CO2emissions ||4,907 ||6,377 ||9,781 ||11,140 ||12,618 ||13,878 |
|CH4 ||1,706 ||1,669 ||1,623 ||1,593 ||1,616 ||1,635 |
|N2O ||47.5 ||45.8 ||45.9 ||46 ||46.2 ||46.6 |
|NOX ||113.4 ||115.8 ||125 ||125.3 ||128.4 ||133.6 |
|CO ||703.9 ||702.5 ||716.8 ||737.5 ||768.5 ||797.2 |
|NMVOCs ||178.9 ||176.2 ||186.7 ||188.3 ||194.7 ||200.6 |
|HFCs ||neg ||neg ||neg ||0.008 ||0.064 ||0.141 |
|PFCs ||0.089 ||0.096 ||0.094 ||0.1 ||0.034 ||0.029 |
|SF6 ||0.023 ||0.021 ||0.007 ||0.023 ||0.184 ||0.183 |
|SO2 ||16.3 ||17.1 ||18.4 ||21.9 ||21.9 ||20.8 |
Source: Ministry for the Environment (1997a).
Figure 5.28: Percentage change in annual emissions of carbon sulphur-based greenhouse gases, 1990-1995
Textual description of figure 5.28
The percentage change in annual emissions of carbon, sulphur-based greenhouse gases between 1990 and 1995:
- CH4 decreased 4.2%.
- N2O decreased 2.1%.
- Cross CO2 increased 7.4%.
- NMVOCS increased 12.3%.
- CO increased 13.2%.
- NOx increased 18.6%.
- SO2 increased 31.3%.
- Net CO2 increased 183%.
Source: Ministry for the Environment (1997).
Figure 5.29: Changes in annual emissions of fluorine-based greenhouse gases, 1990-1995
Textual description of figure 5.29
Annual emissions of fluorine-based greenhouse gases between 1990 and 1995 (estimated from yearly import statistics).
- HFCs: negligible in 1995, 0.141 gigagrams in 1994.
- PFCs: 0.09 gigagrams in 1995, 0.03 gigagrams in 1994.
- SF6: 0.02 gigagrams in 1995, 0.18 gigagrams in 1994.
Source: Ministry for the Environment (1997b)
Carbon dioxide is not the only New Zealand greenhouse gas whose emissions have increased since 1990 (see Table 5.6 and Figures 5.28 and 5.29). This has led some industrial emitters of CO2 to complain that too little attention is being paid to emissions from other sectors, such as transport and agriculture, whose greenhouse gases come from many small, dispersed sources, such as motor vehicles and livestock (Brasell, 1996).
The following greenhouse gases increased between 1990 and 1995: carbon monoxide (CO); other non-methane carbon gases (NMVOCs); sulphur dioxide (SO2); the nitrogen oxides (NO X); hydrofluorocarbons (HFCs); and sulphur hexafluoride (SF6). The last of these, SF6, is the most potent greenhouse gas yet discovered (see Table 5.3) but its seemingly dramatic increase is almost certainly exaggerated. Because actual usage and emission rates of HFCs and SF6 are unknown, estimates are based on the amount imported each year. Imports have risen steeply in recent years, but emissions are unlikely to have risen at the same rate. In fact, they may not have increased at all because the product that SF6 is used in (underground electrical insulation) is believed to have very low emission levels, if any. The Ministry for the Environment is currently funding research on this.
Although yearly emissions of most greenhouse gases increased between 1990 and 1995, three showed a decrease-methane (CH4), nitrous oxide (N2O), and perfluorocarbon (PFC) (see Figures 5.28 and 5.29). The declines in methane and nitrous oxide occurred in the early 1990s as a result of falling sheep numbers and increased forest planting in the agricultural sector (see Table 5.6). These emissions have increased slowly since then, but are expected to still remain below 1990 levels in the year 2000 (Ministry for the Environment, 1994).
The declines are significant because, molecule for molecule, methane, nitrous oxide, and perfluorocarbons have much greater potential impacts on the climate than does carbon dioxide (see Table 5.3). Although their declines were still outweighed by the increase in carbon dioxide emissions, they did limit the overall impact of the CO2 increase. In fact, when the total global warming potential (GWP) of all three gases is calculated, it appears that their combined impact increased by just 0.2 percent between 1990 and 1995, and will have risen by 2 percent at the close of the decade. When other greenhouse gases are added in, the net rise in the nation's GWP is only one or two percent greater, assuming that SF6 emissions are well below their import levels. This means that, if carbon dioxide emissions had been a little lower, New Zealand could have finished the decade with a lower GWP than it began with. However, the agricultural and forestry developments that made this possible cannot be expected to repeat themselves in future decades.
New Zealand is not alone in not meeting its carbon dioxide emission targets, though our 'gross' emissions have risen at nearly twice the OECD rate. Between 1990 and 1995, the OECD countries registered an overall increase in yearly CO2 emissions of 4 percent compared to New Zealand's 7 percent rise (Masood, 1996). Over the same period, however, global carbon dioxide emissions from fossil fuels rose by an average of 12 percent, in part because the non-OECD countries that signed the FCCC do not yet have specific targets for reducing or stabilising their emissions. Emissions rose by 8 percent in Latin America, 12.5 percent in Africa, 30 percent in the Asia-Pacific (excluding New Zealand, Australia and Japan) and 35 percent in the Middle East.
Recognising the inadequacy of current commitments, New Zealand, along with other countries, is now involved in a round of international negotiations, known as the Berlin Mandate process, that is expected to develop stronger commitments for the period beyond 2000. The new commitments are also expected to be legally binding, in contrast to the 'aim to' commitments that countries originally made under the FCCC.
With these international negotiations set to run until December 1997, the New Zealand Government deferred a decision on the foreshadowed carbon charge until early 1998. The Minister for the Environment said that, for effective progress at a global scale, there needs to be widespread adoption of measures, and it is far better that New Zealand act in concert with other nations than act unilaterally. For these reasons the Government decided it would be better to wait for the outcome of the international negotiations before making decisions on additional measures.