Is this the vindication the green economy has been waiting for?

It is important to take a deep breath, resist the urge to use one modest piece of good news as a trigger for environmentalist triumphalism, and start with a cavalcade of caveats.

The news from the University of East Anglia (UEA) that this year is likely to be the first year on record when global emissions have fallen during a period of economic growth is to be welcomed. But this in no way means climate change has been solved. Not even close.

It should go without saying a prospective reduction in total emissions of 0.6 per cent is well below the circa six per cent a year reduction in carbon intensity that needs to be sustained throughout this century if we are to stand a reasonable chance of avoiding "dangerous" climate change. In addition, two years of encouraging data suggesting economic and emissions growth have decoupled is in no way confirmation that we are at the start of an era of emissions reduction. The pursuit of coal-fired economic growth by China's emerging economy cousins or an economic revival in industrialised economies that comes at the expense of climate action could quickly turn the past few years into a false dawn.

Complicating matters further, attempts to deliver steeper and more sustained emissions reductions are compromised by some of the trends that have helped deliver the recent slowdown in global emissions. The shift from coal to gas sparked by the US fracking boom may have helped "bend the curve" for global emissions, but if it continues without parallel progress on carbon capture and storage or a clear plan for engineering a transition to genuine zero emission technologies it will never bend the curve far enough. Gas may turn out to be a "bridging fuel", but a bridge that only gets you half way across a chasm is no bridge at all.

Similarly, on a policy level it is not as if governments and businesses can simply hail the success of the strategies and investments that have resulted in this historic reduction in emissions and promise more of the same. Many of the policies that have mobilised the necessary low carbon infrastructure investment have been imperfect and some have been badly flawed. There is little doubt more cost-effective, popular, and scalable measures are needed if encouraging recent progress on emissions is to be built upon - starting with a genuinely ambitious international climate change agreement from this week's Paris Summit.

And yet it is also important to recognise and celebrate where these policies have got us. The UEA report suggests emissions and economic growth have detached, not because of accountancy tricks or quirks of the weather, but because of massive investment in Chinese renewable energy and energy efficiency that has enabled a measurable slowdown in the country's appetite for coal - an investment surge that has been backed by the sustained reductions in US and European emissions enabled by their own coal to gas and clean energy switch and historic reductions in energy use.

For years, advocates of the green economy have been faced with the considerable challenge of defending policies that at the macro level did not appear to be delivering on their stated aim. The impossibility of proving a negative meant claims that climate policies were leading to a slower increase in emissions than would have been the case inevitably sounded unconvincing. It may have always been the case that climate policies and investments were about laying the foundations for a period of sustained emissions reductions. But accusations from the climate sceptic/lukewarmer/'please book me as a Fox News talking head' crowd that money was being wasted on green technologies that were not delivering promised emissions cuts found it relatively easy to gain traction as long as one country or one industry's emission reduction efforts failed to put a discernible dent in the seemingly inexorable rise of global emissions.

But now the mounting evidence emissions and economic growth has decoupled promises to deliver the green economy the primary evidence it has been craving. There will no doubt still be plenty of set-backs in the future; emissions could climb again, the resilience of a fossil fuel industry more powerful than many governments is not to be underestimated. But it appears increasingly self-evident emissions can be reduced as economic prosperity and poverty eradication continues. Just as it is equally self-evident that it was bold policy and investment choices that delivered the start of this historic transition.

China was only able to unleash its low carbon investment waves once clean technologies were shown to work at scale and in a broadly cost effective manner (and fossil fuels were shown to have catastrophic hidden costs in terms of the pollution they cause). Clean technologies were only able to demonstrate their efficacy thanks to R&D investment and supportive policy environments enacted by enlightened governments.

Climate policies might not have worked as quickly or as effectively as hoped, but they have worked. Ministers gathered in Paris have the final piece of evidence they need. The green economy can deliver, all that is needed now is the leadership and ambition necessary to let it finish the job.