11/03/2014 11:34 pm ET Updated Jan 03, 2015

IPCC's Most Important Finding: We Need a Total Emissions Phase-Out

I woke up this morning in Amsterdam to a front-page headline I never thought I'd see: "By 2100 Emissions Must Go to Zero" (my translation from the original Dutch). Referring to the landmark report of the Intergovernmental Panel on Climate Change (IPCC) released over the weekend, the Volkskrant led with what I consider to be the IPCC's most important finding.

It wasn't the IPCC's biggest headline grabber. That we're headed for "severe, widespread and irreversible" impacts globally received most of the attention. But this should come as a shock only to those who have not been paying attention. That net CO2 emissions need to decrease to zero, on the other hand, not just a percentage reduction by this or that year, is revolutionary.

Let me explain why.

As a concerned citizen, let's say I decide I want to play my part and reduce my CO2 emissions by 10 percent this year. Or 40 percent by 2020. Or whatever (because really, as a resident of a wealthy Western country, how much is my fair share of reductions?). How do I figure out what that actually means in practice? What are my total emissions? What percentage emissions reductions could I achieve by giving up meat once a week, or by becoming a vegetarian altogether? Or by replacing my old refrigerator with a new, more energy-efficient model? Or by driving an electric car?

To be sure, there are online emissions calculators which could help me figure those things out. But I suspect only a hard-core few, relatively speaking, would go to the trouble.

If I know that ultimately I will need to phase out my CO2 emissions entirely, however, and that "ultimately" means sooner rather than later, my outlook changes entirely. I don't need an emissions calculator to figure out what I need to do.

This holds true not only for individuals, but even more importantly for corporations, investors, utilities, governments and others whose actions will literally determine the fate of our children, grandchildren and future generations. Knowing that emissions need to get to zero means that fossil fuels must go. This makes any expansion of coal-fired power, for example, truly a devil's bargain. From now on, any long-term investment which "locks-in" future CO2 emissions must be considered in this context.

Some worry that a long-term goal of phasing out emissions undercuts the urgency of reducing emissions now. 2100? Why that's more than 85 years away! Piece of cake, no need to rush! Even the goal of phasing out net emissions by 2050 -- which is technically feasible and gives us a much higher chance of staving off globally catastrophic climate change -- seems like a long way away.

Indeed, it is still the case that global emissions need to stop increasing and start rapidly declining before the end of this decade. But we can and should communicate this short-term imperative as the first of many milestones required to keep us on track for a total phase-out in the second half of the century.

Apart from being easy to grasp, the call for a total phase-out serves another purpose. Governments have committed themselves to keeping global temperature rise to 2°C (and it's worth remembering that most countries have pushed for a much safer limit of 1.5°C). Just like the difficulty for individuals to translate percentage emission reductions into practical actions, it's hard to hold governments accountable to an abstract concept such as global temperature rise when evaluating concrete national policy measures. No wonder government policies currently add up to a devastating 4°C temperature rise by 2100.

Having a time bound total phase-out goal would help enormously in this regard. Will a proposed development put us on track to achieve net zero emissions by 2050 or shortly thereafter? If not, then it's not in keeping with the 2° limit governments set themselves and shouldn't be allowed. It's as simple as that. The search for oil in the Arctic? Nope. Tar sands? No way.

In practice, phasing out emissions means committing to and planning for a future powered by 100 percent renewable energy. And with the costs of renewables declining rapidly -- in some markets renewable energy sources are already competitive with fossil fuels -- that future could be realized sooner than we think.

If you think this concept is supported only by hard-core green groups, think again. A new initiative known as 'Track 0' is closely monitoring these discussions, and has compiled evidence of increasing support at the highest levels of influence.

The Trillion Tonne Communiqué, for example, signed by nearly 160 influential business leaders, calls for setting a timeline to achieve net zero emissions before the end of the century.

And to Angel Gurria, Secretary-General of the OECD: "I am making a strong call for governments to put us on a pathway to achieve zero net emissions from the combustion of fossil fuels in the second half of this century. Unlike the financial crisis, we do not have a 'climate bailout' option up our sleeve."

The IPCC has made the scientific case for a total emissions phase-out. Hundreds of thousands of people took to the streets in September demanding a solution to the climate crisis. When governments come together in Paris in 2015 to adopt a new climate agreement, they must demonstrate they have been listening.