Since the collapse of the landmark Copenhagen Summit last December, there has appeared to be setback after setback for those who, like me, believe climate change is the most serious problem facing mankind.
Most recently, the US Senate Majority Leader Harry Reid this week decided to withdraw a landmark cap-and-trade bill in recognition of its lack of support in the chamber. This effectively means that there will be no major US federal climate change initiative until at least after the 2012 presidential election.
This follows the confused misrepresentation of climate trends, especially by the Republicans and some British politicians, which appears to have sown further confusion among international publics about global warming complexity; this misunderstanding accounts, in part, for some global warming scepticism and indeed some of the confusion of "Climategate".
Meanwhile, evidence continues to mount that our planet is heating up, including the authoritative State of the Climate Report 2009 released this week by the US National Oceanic and Atmosphere Office (featuring data from the British Met Office). This shows, for the first time, multiple observational records from the top of the atmosphere to the depths of the ocean and concludes that "global warming is undeniable".
Given this backdrop, it is not hard to see why pessimism has grown this year about the future of international efforts to tackle climate change. However, far from this being the disaster that some assert, I believe that we are rapidly reaching the point when the tide will decisively turn. Why the reasons for such optimism amid so much apparent gloom?
First, there is now a much underappreciated movement towards the adoption of nuclear energy across the world. Despite the lack of recognition in the final Copenhagen communiqué, it is estimated by the International Atomic Agency that some 50 countries will have built nuclear reactors by 2030. This will result in a significant shift in the global energy mix and, while nuclear will continue to have vociferous critics, its virtue in the battle against climate change is as unquestionable as renewables such as wind and solar.
Second, in the absence of both a new global climate change deal to replace Kyoto, and more decisive national action by preponderant countries such as the United States, it is now much clearer than even a few months ago at Copenhagen that the centre of gravity of decision-making on how we respond to climate change must move towards the sub-national level, including to those many US cities which are leading the battle against global warming in North America.
The need for such a paradigm shift from a "top-down" to a "bottom-up" approach is becoming clearer by the day. For instance, over the last decade, while the earth's land and sea surface has been warming overall, trends of weather and climate records reveal larger and more unusual local variations – some unprecedented since the end of the last ice age 10,000 years ago. What these data patterns underline is that, while climate change is a reality, it is impacting regions and indeed sub-regions of the world in very different ways. More openness and clarity is needed about this huge complexity as it accounts, in part, for some global warming scepticism.
It is within this crucial context that sub-national governments across the world, including cities, are putting into practice the fact that adaptation needs to build on existing knowledge and infrastructures in local settings. Forming loose collaborative networks is enabling regional facilitation centres, their experts and decision-makers to learn from one another and also draw upon the resources of existing national and international databases and programmes, such as those of the Intergovernmental Panel on Climate Change (IPPC) and the growing number of consortia linking major cities, local governments, and the private sector.
Experience shows that this bottom-up approach works very effectively as it is only generally when sub-national areas, such as cities, learn how they will be specifically affected by climate change that widespread, grassroots political action can be aroused.
I am therefore delighted at the increasing numbers of regional monitoring centres across the world, which are contributing towards local adaptation plans. In China, where provinces require targets for power station construction, regional environmental and climate change centres are now well developed. In the US, reports have highlighted the value of non-official centres, such as a severe storm centre in Oklahoma, which gives independent advice to communities and businesses, while relying on government programmes for much of the data. In Brazil, regional centres are providing data and predictions about agriculture and deforestation, and inform legislation about policy options.
What this activity points to is the need for a broader global network of such centres to support national climate initiatives, and to facilitate international funding and technical cooperation in delivering the right information to the right place at the right time.
Local actions can only be effective if measurements of climate and environment are made regularly and are publicised as well as information about targets, and projections of emissions. Experience shows that full exposure is needed about what is happening, what is planned, and how every individual can be involved (as the Danes show, for instance, by their community investment in wind power).
Taken overall, and despite recent setbacks such as the demise of the US cap-and-trade bill, I am therefore increasingly optimistic that the tide is turning decisively in favour of tackling climate change, but that it will be the cumulative effect of sub-national actions which will prove crucial in determining the speed and effectiveness of responses to climate change. While international and national policy will still have a key role to play, the message is nonetheless clear: "localisation of action and data" must and will increasingly be the priority in tackling the global warming menace.
Lord Hunt is Visiting Professor at Delft University and former director-general of the UK Met Office