Dr Andy Reisinger, Senior Research Fellow - New Zealand Climate Change Research Institute, Victoria University of Wellington.

"The deal reached in Copenhagen is a crucial breakthrough because it provides for verifiable emissions reductions targets by most of the world's largest emitters. As such, it is an very important political statement with global implications. "The devil is in the details though. It is worrying that even those countries that brokered the deal have admitted that the specific emissions targets will not be stringent enough to reach their stated long-term goal, which is to limit global average temperature increases to no more than 2C above pre-industrial levels. We will have to wait until the final numbers are on table to see how far the actual emissions targets fall short of that ultimate goal, and what amount of warming we might expect more realistically once the dust and celebratory rhetoric has settled. "It is unclear at this stage what this deal means for New Zealand, because most of the rules by which emissions targets will be set and measured are not clear. The agreement does send clear messages from the world's largest economies that they take climate change seriously, and that they expect emissions reductions to be subject to international consultation and analysis.

"The deal includes a long-term target for industrialised countries to reduce their emissions, individually or jointly, by at least 80% below 1990 levels by 2050. If New Zealand wants to be part of this club, it will have to either reconsider its own long-term target, which provides for emissions reductions of only 50% by 2050, or come up with sound and credible reasons that are acceptable to the international community why it should be treated differently, even many decades into the future."

Visiting Professor, Suzi Kerr, Stanford University, Department of Economics & Senior Fellow, Motu Economic and Public Policy Research comments:

"The agreement on a transparent monitoring mechanism is a relief and a major step forward with respect to some key developing countries. Elinor Ostrom (Winner of the 2009 Nobel prize in economics) has found that to build trust and cooperation without external enforcement, a key prerequisite is that they have credible information about each others' actions so they can reward and penalize each other. Transparent monitoring is by no means sufficient to successfully address climate change on a global scale but is a critical necessary step.

"The fact that the agreement is not legally binding may not be that critical given that international agreements are essentially unenforceable in any case. It may however weaken the pressure to comply.

"We will need to see the details of the final agreement to understand how this will affect countries' abilities to make part of their contribution to the climate effort through paying other countries to go beyond their agreed targets. We may need a separate legally binding agreement between countries that will be linked in a common emissions trading system. Trading is critical because it allows us to contribute beyond the opportunities for emissions reductions within New Zealand. As a rich country we should be prepared to be generous in our contribution to the global effort.

"However we don't want to waste our resources with unnecessarily high cost domestic actions. We won't be able to achieve the awesome task before us unless we can do it in the smartest most efficient ways possible and that requires that we pay for actions in developing countries. Emissions trading (cap and trade) is the best currently available instrument for achieving the enormous transfers required. The Clean Development Mechanism is not effective because 'reductions' are measured relative to an unobservable counterfactual and a large percentage of the apparent reductions are not real. This problem can be avoided if we are trading with countries with verifiable national targets.

"It is too soon to judge the success of the agreement but we need to remember that climate change is the ultimate free rider problem, it is costly and it involves profound distributional issues. Any agreement that involves meaningful verifiable reduction targets from most of the major emitters, builds on the flexibility of the previous agreement and creates a stronger framework for moving forward will be a major achievement. We should not only look at the achievements as a glass half full but remember that without the enormous effort of many people, including many New Zealanders, that glass would still be close to empty."

Source: Science Media Centre