Why the Climate Change Commission's targets are so weak
OPINION: Of all the many things the Climate Change Commission has been asked to advise on, the emission budgets are the most important. These describe the total amount of all greenhouse gases released into the atmosphere. Issued in five-year chunks, they keep us on the road to our 2050 net zero target. They also form a key part of our obligations under the Paris Agreement, to make sure that our contribution is ambitious and fair. The commission is proposing emissions of 628 million tonnes of carbon dioxide-equivalent in the decade 2021-2030. How ambitious is that? READ MORE: * Compact cities, low-methane sheep and EVs: Life in our zero-carbon future * The price of ambition: $2-11bn to up our climate pledge to the UN * The change that'll make Rogernomics 'look like a trial period' The short answer is: not ambitious enough to meet the goal of keeping global warming to 1.5 degrees Celsius. The line of argument pursued by the commission is that if we met the average reductions needed globally, for each of the different greenhouse gases, the budget would come out to 564m tonnes. They admit that simply meeting the global average isnt enough (were a rich country whose historical contribution to climate change is about six times the world average). And yet, the proposed budget of 628m tonnes is higher than 564m tonnes. They invite the public to comment submissions close on March 28 . But its worse than that. These figures reflect the particular carbon accounting methods which have been applied by the commission. The choices that have been made make our contribution a 30 per cent reduction on 2005 levels by 2030 look far better than it really would be. The first of these is called gross-net accounting. The 2030 target is for net emissions: we get to subtract off the carbon stored in trees from our gross emissions from burning fossil fuels and agriculture. Yet, its compared to gross emissions in the baseline year. This artificially bumps up our past emissions, making the future targets look better. The second is shifting the base year. Many climate targets use a base year of 1990. For example, the EU has a target of reducing emissions by at least 55 per cent by 2030 compared to 1990. (That works out to at least a 41 per cent reduction over 20182030.) By shifting the base year to 2005, we are letting ourselves off the hook for our rapid increases in emissions in the 1990s. Again, choosing higher baseline emissions in the past makes the targets look better. The third is the treatment of forestry. Here there are two main choices, Greenhouse Gas International (GHGI) accounting and Nationally Determined Contribution (NDC) accounting. The first is used by all countries in their annual reports to the UN, the second arose out of the Kyoto Agreement. The differences are quite technical and are discussed in detail in the commissions reports. Essentially, GHGI is what the atmosphere and the climate actually sees in each year; NDC accounts better for the impact of activities like tree planting and forest clearing. How do our emissions look under the two methods? Even under the Commissions preferred NDC accounting, the proposed target is weak: a 4 per cent reduction from one decade to the next. But under GHGI accounting, which is what the world will see and what the climate will see, its a 13 per cent increase. Why do the targets look so weak? The big challenge the Commission has dealt with is that, in the past, a large part of our climate strategy was based on planting trees. And initially, vast numbers were planted: 494,000 hectares of new forestry between 1990 and 2003. But over the following decade and a half, that came to a crashing halt, with net clearance of 29,000 hectares. Just to stand still we would now have to repeat the tree planting of the 1990s. But the commission knows that we cant rely too heavily on trees, because its a short-term measure, unfair to future generations. We are the future generation now facing up to what we chose in the past. That short-term measure from the 1990s is now coming home to roost. What would be a better target? One number suggested by the commission does stand out: 524m tonnes. Thats what they call the upper quartile of the global commitment for 1.5C. Accepting the commissions forestry model, this would require gross emissions of long-lived gases to fall over 40 per cent by 2030, which conveniently matches the EUs recently-updated 2030 target. And it comes close to the calls from environmental groups for fossil fuel burning to halve in the next decade. 524m tonnes may be ambitious; but its the highest budget that could responsibly be adopted, having regard to the scientific advice on what needs to be done to avoid global catastrophe, and the highest budget that could reasonably be called fair, in terms of our contribution to the global goal of keeping warming to 1.5C. Robert McLachlan is a distinguished professor in applied mathematics at Massey University and writes on climate and environmental issues .