New Zealand's commitment was to reduce its greenhouse gas emissions by 30 per cent from 2005 levels and 11 per cent from 1990 levels by 2030.
This was criticised by some quarters as "weak" and only a little stronger than the previous target for 2020.
Victoria University's Dr Adrian Macey described it as "the minimum credible target", particularly as New Zealand had already put on the table a conditional target of 10-20 per cent below 1990 by 2020, and already had its unconditional five per cent below 1990 by 2020 target.
As the signing in New York gets underway, there have been a trio of big reports that have come out in New Zealand this week.
The Morgan Foundation's investigation
On Monday, the Morgan Foundation released a report claiming the foreign carbon credits which New Zealand bought to reach its climate targets were fraudulent.
Founder Gareth Morgan said: "We are, without doubt, cheats."
New Zealand was the world's biggest buyer of Russian and Ukrainian credits which did not represent any reduction in greenhouse gas emissions - and which meant that its on-paper target fell short of what would actually be achieved.
It focused on New Zealand's credit-buying under the Emissions Trading Scheme, our main tool for climate mitigation, which allows polluters to off-set emissions by buying carbon credits from companies which capture emissions, such as the forestry industry.
Until recently, credits were also able to be bought from other nations that had signed up to the Kyoto Agreement, but those sold by Ukraine and Russia were virtually hot air.
"Proportional to our emissions, New Zealand has been by far the largest purchaser of these Ukrainian and Russian credits through our Emissions Trading Scheme," said report co-author and economist Geoff Simmons.
"This was due to deliberate decisions by the National-led Government to -- unlike any other country -- continue allowing unlimited use of these and other foreign credits for as long as the international community let us."
Climate Change Minister Paula Bennett, who is in New York for the signing, responded to the report by saying "New Zealand made the best decision based on the rules at the time".
The ETS was now being overhauled and Ms Bennett said she still stood by its "ability to help us transition to a lower carbon economy, and international markets have a role to play in that".
Because of New Zealand's emissions profile, carbon-trading would remain the biggest mechanism through which to meet the new target.
The Royal Society of New Zealand's report
A report released on Tuesday by the Royal Society of New Zealand powerfully highlighted why action is so urgently needed to combat climate change.
It provided a stocktake of how and why New Zealand would be hit by the impacts of a warmer world.
Unless drastic measures were taken to reduce global emissions, climate change would almost certainly accelerate this century.
Changes expected to impact New Zealand include at least 30cm and possibly more than one metre of sea-level rise this century.
The report finds it likely that the sea level rise around New Zealand will exceed the global average, which would cause coastal erosion and flooding, especially when combined with storm surges.
The implications for coastal populations would vary widely, but it's estimated thousands of households in many towns and cities will be affected.
These communities would need to plan for and adapt to change and some will need to decide whether to "hold the line" or relocate in response to known risks or actual climate change impacts.
Further, climate change would bring more floods (around two thirds of Kiwis live in areas prone to flooding); make our freshwater problems worse and put more pressure on rivers and lakes; acidify our oceans; put even more species at risk and bring problems from the rest of the world.
While New Zealand agriculture could benefit from increasing global commodity prices in the long term, there were many negatives, the report said.
Reduced food security, increased displacement and migration, and potential political instability suggest that patterns of international trade, demand for services, and international tourism, could change substantially in the future as a consequence of climate change.
The society's president, Emeritus Professor Richard Bedford, said the report was sought to provide a clear summary of the scientific evidence and projections of climate change, and to identify the key risks.
"It is critical to communicate clearly New Zealand's sensitivities to climate change and the need for responsive systems to address them," he said.
"All New Zealanders will be affected and must be involved in the discussion."
Pure Advantage's discussion paper
Finally, green business think-tank Pure Advantage has today put out a report proposing a novel approach to climate mitigation: planting billions more trees.
The group calls for a new national forest strategy that would halt deforestation and ultimately create 1.3 million hectares of new forest.
It argues that planting huge new blocks of permanent native forest and fresh high-carbon commercial forests could avoid large areas of land being lost to erosion, help off-set agricultural emissions and put the country on course for a net-zero greenhouse gas future.
Along with erosion-prone land, new forest should also be planted along waterway margins and urban forest, where the environmental benefits of trees, such as protecting river ecosystems, would be much greater.
The Government has already stated that 1.1 million hectares of land is currently erosion-prone.
Covering the entire amount in native trees would avoid hundreds of millions of dollars of lost value, while sucking nine million tonnes of carbon dioxide from the atmosphere every year.
New Zealand needed to expand its forest cover, prioritise forest that would remain permanent, allow for diversity in forest stocks and bolster measures to protect them, the report's author, Dr David Hall, said.
It pointed to a shortage of capital as the biggest obstacle to new forest planting, but suggested ways that tree-planting could pay off -- particularly by strengthening relations of responsibility between polluters and "anti-polluters".
Further, it recommended options to fix the ETS.
To better incentivise planting, the report suggested that landowners should have a "smorgasbord" of funding options to pick from depending on their circumstances.
Beyond the Afforestation Grant Scheme and other Government mechanisms like the Permanent Forest Sink Initiative and Erosion Control Funding Programme, it suggested bigger and bolder measures.
These included creating a meaningful carbon price, greater support for community conservation through voluntary offsetting and donations, slashing the actual capital required for planting, state-guaranteed "climate bonds" for forestry investors, funding more QEII covenants and exploring a polluter-pays "environmental consumption tax" independent of the existing ETS.
The report has been welcomed both by the forestry industry and Associate Minister of Primary Industries, Jo Goodhew.
