Over the five years from 2008 to 2012 inclusive, emissions totalled 373 million tonnes, which was 63 million more than the country's commitment under the Kyoto climate treaty. But that was offset by 72 million tonnes of removal units New Zealand will receive for the net uptake of CO2 from the atmosphere by "Kyoto" forests (those planted since 1989 on land not previously forested) after accounting for deforestation, when plantation forests are not replanted after harvest and the carbon in the felled trees is deemed to be emitted.
Consequently New Zealand will meet its obligations under Kyoto's first commitment period. The Government has declined to sign up for the second, which began last year.
Net removals by forestry in 2012, as measured for Kyoto purposes, were 15 million tonnes, down from 16.8 million tonnes in 2011.
The Ministry for the Environment said an additional 7000 hectares was deforested, making a cumulative 30,000ha between 2008 and 2012, and 151,000ha since 1990.
A separate report from the Ministry for Primary Industries (MPI) indicates that the ability of an expanding plantation forest estate to offset emissions growth is dwindling.
Its survey of 29 commercial forest nurseries last year found 54 million seedlings sold, down from 73 million in 2012 and 68 million in 2011.
MPI estimates the area of new planting (that is, excluding the replanting of harvested land) last year was 4000 hectares, down from 12,000 in 2012 and a peak of just under 100,000 in 1994. These trends contrast with the global picture as described by the United Nations' Intergovernmental Panel on Climate Change (IPCC) for what it calls the agriculture, forestry and other land use (AFOLU) sector, which accounts for about a quarter of net global emissions.
Largely due to decreasing deforestation rates and increased afforestation, the IPCC projects net annual emissions from AFOLU will decline, potentially to less than half the 2010 level by 2050.
Forest Owners Association chief executive David Rhodes said that from 2008 to 2012 the country's 25 per cent increase in carbon emissions was masked by carbon stored in forests planted in the 1990s.
"As these trees are harvested, forestry will move from being a carbon sink to being a carbon source," Rhodes said. "At that point New Zealand's environmental credentials will be delivered a double whammy. Our steady increases in gross emissions will no longer be masked by forestry and, indeed, forestry emissions will add to the negative [side of the] ledger."
Rhodes said the Government portrayed the emission trading scheme as a success because the Crown had a surplus of credits at the end of 2012.
"But that has little or nothing to do with the ETS. It's all due to a boom in forest planting in the 1990s. Since then we have moved to net deforestation, a trend that appears to be gathering pace."
The greenhouse gas inventory recorded New Zealand as having 91 million more Kyoto units on its books than it needed to meet its Kyoto obligations. But that reflected emitters importing 90 million cheap international units from the international carbon market and using them to meet their obligations under the ETS in preference to New Zealand units allocated to forest owners as partial compensation for their deforestation liabilities.
The resulting collapse in domestic carbon prices has meant the ETS presents a low barrier to exit from forestry to other land uses.
Carbon credits-debits
• Grew by 1.7 million tonnes of carbon dioxide equivalent in 2012 - a rise of 2.2 per cent.
• 373 million tonnes in total between 2008 to 2012 - 63 million more than the country's commitment under Kyoto.
• Offset by 72 million tonnes of removal units New Zealand will receive for the net uptake of CO2 from the atmosphere by "Kyoto'' forests.
• New Zealand will meet its obligations under Kyoto's first commitment period.
• The Government has declined to sign up for the second, which began last year.