Halldór Thorgeirsson, Director for Strategy at the UN Climate Change Secretariat, gave a speech to the 2015 Arctic Frontiers Conference on Climate and Energy, in Tromsø, Norway, on 19 January.

Mr Thorgeisson noted that 2015 is a year for decision making on climate and on development more broadly. Governments are scheduled to reach a new, universal climate agreement in Paris, in December, that puts the world on track to stay below a 2C degrees temperature rise and achieves global climate neutrality in the second half of the century. The key message of his analysis is that:

It is still possible to stay under this limit AND achieve legitimate development aspirations and eradicate extreme poverty. But further delay will increase the costs and increase the risk of major disruption resulting from abrupt policy changes.

The full speech follows:

Building Sound Climate Policy on a Firm Scientific Foundation

Thanks for this opportunity to outline the policy response to the scientific case for urgent and long-term action on climate change. This scientific case has never been stronger.

This foundation has been built through research, observations and assessments culminating in the recently completed Fifth Assessment Report (AR5) of the IPCC.

There is absolutely no basis to suggest that we, as a community of nations, don’t have a sufficient basis to now make decisions to respond to the science.

This year, 2015, is a year for decision making on climate and on development more broadly with profound implications for the trajectory of economic development and global prosperity for decades to come.

While there are ample reasons to be concerned about adverse effects of climate change, there is also a basis for optimism. It is still possible to avoid the worst impacts of climate change and doing so will bring huge benefits when we look at the bigger picture.

I serve the UN Framework Convention on Climate Change, a treaty with universal membership of nations. This treaty, signed in Rio in 1992, is a planetary risk management treaty. Its objective is not to prevent climate change, which is clearly not feasible. It is designed to limit climate change to a level which avoids "dangerous interference with the climate system".

Governments came together under the banner of this Convention in direct response to the first assessment of the Intergovernmental Panel on Climate Change (IPCC). riding on the wave of a major geopolitical thaw at that time resulting from the end of the Cold War. As you know, Arctic cooperation as we know it today can also be traced to that turning point.

Understanding the Implications of the 2C Limit

The Earth system is complex and long-term policy direction can only be based on long-term observations and comprehensive assessments of the best available science.

So, who decides what constitutes "dangerous interference" with the climate system?

Such a decision is clearly not for any one nation to make given the global implications. Deciding how much risk to accept has profound ethical dimensions given the reality that a changing climate has greatest consequence for vulnerable populations within nations (rich or poor) and for vulnerable nations (generally poorer nations).

The fundamental rationale, therefore, for an international climate treaty is to provide a platform for collective decision making on the Earth's climate with all nations at the table.

Governments have agreed to set the upper limit of acceptable warming at 2degrees C above the pre-industrial level. This was a political decision in the light of science.

There is some confusion on this 2 degrees C limit. It is important to understand that:

• There are significant risks and adverse effects associated with any levels of climate change as can be seen from impacts we are already experience at less than 1 degree C warming.
• Warming is not even over the Earth's surface and warming here in the Arctic significantly exceeds the global average.
• Setting the upper limit of acceptable warming is not a question of feasibility. This is collective planetary risk management. Humankind has drawn a defense line. It will not be easy to defend but the consequences of failure have been deemed unacceptable.

Not Possible to Delay Adequate Action

Let's be clear. Continuing current policy would put the planet on track to more than 3 degrees C warming.

This is why Governments decided to negotiate a new agreement under the Convention applicable to all and to mobilize climate action through unprecedented cooperation of national, subnational and local government, the private sector and civil society.

This agreement will be adopted in Paris, in December of this year. This morning you heard Laurent Fabius speak about his vision for the Conference.

The objective is to put in motion a fundamental transformation in the way we use and produce energy, how we plan our cities, how we manage land and how we prepare for a changing climate and cooperate to minimize its disruptive effect.

Transformation takes strategy. You need to know your destination if you are serious about reaching it.

Why is there a need for fundamental transformation? Can we not fix this with adjustments and improvements?

This is where we need to go back to what science tells us about the remaining flexibility and time we have.

The IPCC has started to put numbers on the cumulative amount of CO2 emissions that could be emitted and still stay under the 2C limit. The stark reality is that we have used two thirds of this cumulative amount leaving only 1000 Gt CO2 that could be emitted and still stay under the 2C limit.

It is imperative that this remaining amount of emissions be deployed in a manner that brings maximum development and societal benefits. Wasteful emissions devoid of broad economic benefits can no longer be justified.

Global emissions will need to stop rising and start declining soon. By 2030, global emissions will need to have turned the corner and be 10 per cent below 2010 levels.

Climate Neutrality Necessary in Second Half of Century

At some point in the second half of this century, all emissions need to be balanced by uptake from the atmosphere. The planet needs to reach a climate neutral state. This is also referred to as net-zero.

The key point to underline here is that it is still possible to stay under this limit AND achieve legitimate development aspirations and eradicate extreme poverty. What's more, this transition will bring huge co-benefits, which are powerful motivators for change.

But this takes strong political will and a simultaneous focus on the urgency and the long-term imperatives. Business and investors are calling for long-term signals. This clarity will also unleash the power of innovation.

Putting a price on carbon is the most powerful tool available to decision makers to ensure that the long-term carbon constraint will be factored into economic decision making.

Recent estimates demonstrate that making the infrastructure investments we know will be made in the next fifteen years compatible with climate protection adds less than 5% to the total known cost.

Further delay will increase the costs and increase the risk of major disruption resulting from abrupt policy changes.

In other words, we are faced with a choice between transformation or disruption.

How the Paris Agreement Must Help

So, what implications does all of this have for the Paris agreement?

The first step will be bottom-up. Intended nationally determined contributions to the objective of the Convention are to be communicated well in advance of the Paris conference, and by the end of March by those countries ready to do so. In November, the Heads of State of China and the United States of America jointly announced in Beijing their contributions and Heads of State of the EU have agreed their 2030 target.

The secretariat will, by 1 November, issue a synthesis report on the aggregate effect of contributions communicated by 1 October.

These contributions will cover the period from 2020 to 2025 or 2030. The new treaty will be for the longer term and will provide for further cycles of commitments and for a strategic review of progress towards the objective in light of reporting on implementation, on impacts of climate change and the evolving understanding of the climate system and of the available solutions.

The aim is also to reach agreement on milestones along the pathway of global emissions at least for 2050 and perhaps 2030 as well. The reality of the numbers indicates that global emissions need to be halved by 2050. The reality that climate neutrality needs to be achieved in the second half of the century will also need to be recognized explicitly. This would send a powerful signal to investors, designers and innovators and give us all clarity on the destination.

The Paris Conference will mobilize uprecedented cooperation and determination to deliver by national governments, city councils, corporate board rooms and civil society to contribute to the transition. The momentum for change is already huge and growing as was demonstrated at the UN Secretary General's Summit in September of last year.

As HRH Prince Albert II of Monaco reminded us this morning, we cannot succumb to a sense of impotence and powerlessness as we face the complexity of this problem. We need to keep our eye on the horizon and move forward one step at a time.

UNFCCC's Halldór Thorgeirsson speaking in Tromsø, Norway