ghg-inventory-1990-2013

Chapter 2: Trends in greenhouse
gas emissions
2.1 Emission trends for aggregated greenhouse
gas emissions
This chapter describes trends for aggregated GHG emissions by gas. For each gas,
interpretation of the emission trends is based on the contributing Inventory sectors and
major categories. Emission trends for each Inventory sector can also be found in the
Executive Summary (section ES4) and in chapters 3–7 of this report, as a part of each
sector overview.
2.1.1 National trends
Total (gross) emissions
Total (gross) emissions include those from the Energy, Industrial Processes and Product
Use (IPPU), Agriculture and Waste sectors, but do not include net removals from the
Land Use, Land-Use Change and Forestry (LULUCF) sector. Reporting of total
emissions excluding the LULUCF sector is consistent with the reporting under the
Climate Change Convention.
1990–2013
In 1990, New Zealand’s total greenhouse gas emissions were 66,720.16 kt carbon dioxide
equivalent (CO 2 -e). Between 1990 and 2013, total greenhouse gas emissions had
increased by 14,241.5 kt CO 2 -e (21.4 per cent) to 80,961.6 kt CO 2 -e in 2013 (figure
2.1.1). From 1990 to 2013, the average annual growth in total emissions was 0.9 per cent
per year.
The emission sources that contributed the most to this increase in total emissions were
road transportation, public electricity and heat production, agricultural soils, consumption
of halocarbons and sulphur hexafluoride (SF 6 ), and enteric fermentation. 10
2012–2013
Since 2012, New Zealand’s total greenhouse gas emissions have decreased by 1,116.3 kt
CO 2 -e (1.4 per cent). This reflected emission reductions in the Energy, Agriculture and
Waste sectors (3.2, 0.4 and 0.5 per cent respectively) that were partially offset by a
2.3 per cent increase of emissions from the IPPU sector.
Emission reduction in the Energy sector reflected a decrease in emissions from electricity
generation and fugitive emissions. Emission reductions in electricity generation were
driven by high hydro inflows in catchment areas in 2013, which led to an increase in the
share of electricity generated from renewable energy sources. A higher contribution from
renewable energy in the national grid resulted in a lower proportion of fossil fuels-based
electricity generation over the year. Reductions from fugitive emissions are primarily
caused by reduced activity in underground coal mining and handling category.
Total agricultural emissions in 2013 were lower than the 2012 level, which is attributable
to the unfavourable weather conditions (drought in 2013). There was a decrease in the
10
Methane emissions produced from ruminant livestock.
New Zealand’s Greenhouse Gas Inventory 1990–2013 31