... and on that yes the future world depends.[1]

I'm just back from spending a whirlwind 48 hours in Abu Dhabi where more than a thousand people, including 70 Ministers and numerous business leaders gathered to prepare for the UN Secretary General's Climate Change Summit taking place 23rd September. By then polluters are expected to come up with bold ideas and commitments to cut greenhouse gas emissions faster.

Wind Park Gunfleet Sands in the North Sea. 01/15/2013 © Paul Langrock / Greenpeace

I came away feeling optimistic about the buzz around real action which is beginning to take place in cities and on private finance. But I am even more concerned by the inconsistencies in public policy which persist when it comes to understanding what the international commitment to "staying below 2 degrees Celsius" actually means. In plain English, it means it's game over for fossil fuels.

Just three weeks ago, the Intergovernmental Panel of Climate Change (IPCC) underscored the need for "a fundamental transformation" of our energy system to prevent catastrophic warming, including a "long-term phase-out of unabated fossil fuel conversion technologies". Reducing emissions a bit here and there isn't going to do the trick, as eventually global net CO2 emissions must simply "decline toward zero". To get there in time, phasing out of fossil fuels must start today. Judging from the speeches I heard in Abu Dhabi, governments haven't quite gotten the message yet.

In Abu Dhabi former US Vice President Al Gore gave an inspirational keynote address on the transformation needed in a number of action areas. Gore said there were just two questions: do we really have to do this and can we do this. He answered unequivocally yes to both. The business community and investor community are already moving and are ahead of governments, but investors who got burned on sub-prime mortgages don't want to get burned a second time so are doing their homework. He called for a price on carbon and a price on denial in politics, vividly painting a picture of what is clearly right and what is clearly wrong in what he likened to the moral equivalent of ending slavery.

In making the case for "the role of business in climate action" Paul Polman, CEO of Unilever underscored the fact business look to governments for "clarity, confidence and courage". From my own discussions with progressive business representatives they are clearly chafing at the bit and want to see a price on carbon. The investment community seems to be developing innovative instruments to tap into the private investment flows, with particular efforts around green bonds. If sexed up, these products have the potential to both trigger the much needed snowball effect within the investment community and scale up green finance. Green bonds are a good way to illustrate how a shift in investments towards RE is feasible if the right signals are sent to the market by key players. This is the type of bold and tangible action which investors can take towards the UNSG's Climate Change Summit in September. And by the way, this is not altruism but smart investment!

What is less clear is where public finance is going to flow and the strategic role it can play in de-risking private capital. Equally unclear is how the $100 billion Copenhagen commitment could build to the $1 trillion needed for the transition. As Achim Steiner, Executive Director of UNEP noted," if you can't finance it, forget about it." That said, contributions to capitalize the Green Climate Fund are the kind of announcements leaders should bring to the Summit in September, to get this ball finally rolling.

The cover of this week's Economist asked "What would America fight for?" offering the US delegate to the Abu Dhabi Ascent an opportunity to signal the Obama Administration's commitment to combatting climate change. With John Podesta at the White House and John Kerry at the Department of State there seems to be a renewed focus on demonstrating US engagement and leadership in limiting carbon emissions. Yet, the signals from the U.S. aren't convincing. As we said in our response to the release of the U.S. National Climate Assessment: "Fossil fuel extraction and exports remain a major blind spot in the Obama administration's climate action plan, and we hope the President will recognize that to protect Americans from the worst impacts of climate change, we must keep most fossil fuels in the ground."[2]

Imagine if Heads of States actually took the warnings of scientists seriously.

Imagine President Obama and Premier Li both announced a "war on coal".

Imagine if Chancellor Merkel announced the German development bank KfW was ending its financial support for coal.

And imagine if Prime Minister Abe made a similar announcement about Japan.

Those could be ambitious actions leaders could bring to the UNSG's Climate Change Summit in September.

Today we are just 15 months away from the moment when world governments are expected to agree on a new climate treaty in Paris. To catalyse the fundamental change scientists are calling for, the Paris Protocol must mark the beginning of an end of the fossil fuel era and an acceleration towards a 100% renewable energy future for all. Citizens, companies and investors need convincing signals from leaders that the world is moving away from fossil fuels. This is the spirit we hope to witness already in the commitments Heads of States and business leaders will bring to the Climate Summit in September.

We, as civil society, are ready to play our part, by helping design and implement solutions to climate change and by ensuring that public pressure for action continues to mount.

Patricia Lerner is a Senior Political Advisor at Greenpeace International.

[1] US poet Wallace Stevens "The Well Dressed Man With A Beard" published 1942.

[2] The National Climate Assessment reminds us that climate change is already having major impacts on our health, communities, and environment, and the threat of stronger storms, droughts, and rising sea levels will only grow unless we reduce carbon pollution. "President Obama has taken some important steps to address climate change at home, but unfortunately, his administration is undermining that progress by ignoring the huge amounts of carbon pollution that would accompany the fossil fuel industry's plans to export coal, liquefied natural gas, and oil abroad. Climate change is a global crisis which will only be made worse by extracting and exporting fossil fuels, whether it's fracked gas from Appalachia, coal strip mined from Montana, or oil drilled from the Arctic." "Fossil fuel extraction and exports remain a major blind spot in the Obama administration's climate action plan, and we hope the President will recognize that to protect Americans from the worst impacts of climate change, we must keep most fossil fuels in the ground."