The prescription ... what we need to do

Taking the medicine

Figuring out what we have to do about the climate problem isn't actually very hard. We've pretty much known for 30 years.

But we haven't done it.

Instead we talk a lot about doing things that won't fix it.

Why is this? Here are a couple of suggestions:

•  The threat is insidious - it doesn't ring our alarm bells the way more immediate problems do.

•  Fossil fuels have been very good to us. Apparently we're not yet persuaded there's a good enough reason to give them up.

•  The fossil fuel economy is enormous and politically powerful. There is industrial resistance.

•  The climate problem has become entangled in the politics of the environment, and (for the moment) intractable ideological & cultural conflicts.

This isn't really unique - it shares a lot with past episodes of difficult change like the abolition of slavery. Surely what we need more than anything is that ordinary folks understand well what we are up against. Nobody - not the toughest oil man or the meanest politician - wants bad stuff for their grandkids. Without a well informed public, the problem won't be solved ... at least not in time. But if enough people know what is at stake and what must be done ... anything can happen. That is our hope and our inspiration.

Here is a simple prescription. To be any good, a remedy has to be based on a correct diagnosis and a good understanding of the causes. This one is.

It might strike you it doesn't look like what you normally hear ... 2050 targets; 2℃ barrier, etc ... that's because these are political formulae, not rational responses. Essentially, our leaders are treating this as a political/economic problem, when it is a geophysical one. We can't choose a treatment because it tastes good; we need to find the one that works.

by any means. It won't restore the world to its pre-warming state - it's too late for that. But it can limit warming to less than 1.5℃, and restore Earth to approximate energy balance in about a century. It entails a transition to a zero-carbon energy system, starting without delay. It means the assets of fossil energy companies must be left unexploited. It probably means we will need more nuclear energy; and we will have to be serious about getting CO2 out of the air for the next hundred years or so until we reach a safe level - not more than 350 ppmv ... maybe less.

All these imperatives derive from the understanding that the climate problem is best defined as one of planetary energy imbalance. To think of it any other way is to miss the point ... like prescribing aspirin for pneumonia. You can cure the planet's fever by removing its cause - not otherwise.

The prescription is due to Dr James Hansen, retired director of the Goddard Institute in New York & one of the best scientists and advocates working on the problem. He is also a grandfather who has understood that if we are in a position to act, and yet fail to do so, we will leave a colossal and unsolvable problem for future people to manage as best they can. To him, the thought of such grave neglect is intolerable, so he has spent the last 30 years with his scientific colleagues in the effort to figure out as much as we can about the best way to solve this on behalf of our descendants.


• Earth's positive energy imbalance is currently about 0.7 W/m2.

• Forcings acting on the climate system are dominated by anthropogenic (man-made) ones - both positive and negative.

• Long-lived greenhouse gases are by far the biggest positive forcing; CO2 is the largest individual agent.

• The man-made negative forcings (blue on the chart) are about equal to the combined effect of the non-CO2 greenhouse gases (methane, N2O, CFCs, tropospheric ozone), and so effectively cancel them.

• The three principal negative forcings - opaque aerosols (smog, haze, etc) from factories and fires, and conversion of forest & grasslands to cultivation or wasteland - reflect more sunlight from the surface and atmosphere ... that's how they exert a cooling effect.

• If these continue, we don't need to get CO2 back to 290 ppm - at least not right away. Approximate energy balance will occur at about 350 ppm.

• On the other hand, if we seriously reduce the output of opaque aerosols, the CO2 target would need to come down.

• The energy system is very wasteful - essentially because the stuff has been so cheap for so long. There must be a big efficiency program.

• Tropical forestry is destructive and wasteful. Experts are certain we can harvest forest products and manage these assets sustainably by replanting large areas of deforested land.

• Arable lands and rangelands all over the world are deficient in soil carbon. Long-term carbon sequestration in soils is not only feasible on a large scale, but very beneficial to farmers and ecosystems.

• A big program of tropical reforestation and soil enrichment would be capable of withdrawing 100 Gt of carbon over the rest of the century - enough to lower CO2 by 50 ppm.

• In terms of public policy, the key issue is delay. CO2 lasts a long time. If we begin 5% annual global emission reductions by 2020, CO2 would be above 350 ppm for about a century; but if we don't start until 2030, it's 300 years; after 2050, it's more than a thousand.

• The only way to make a transition from fossil fuels is to make them "pay their way" - that is, the cost of adding their combustion products to the air must be included in their price. That means a "carbon fee" - not collected and consumed by politicians, but returned directly to citizens as a dividend, to create incentives for energy consumers and producers to get engaged with the transition.

Hansen's thinking centres on the question: what is the quickest way to restore energy balance? Delay means more time for ocean-stored heat to melt ice sheets. It means steeper emission reductions ... even a decade or two would require 9 or 10% annual reductions ... and we must commit to abandoning fossil fuels now. Promised reductions at mid-century are not what we need, and misleading.

In the charts above you can see the size of both positive & negative forcings; and the effect of delay in starting to lower emissions. These four lines are for comparison - they don't show the net effect of active CO2 draw-down. With reforestation and soil sequestration, the blue line would reach 350 ppm about 2100.

Jim Hansen has written a lot about this. The link above will get you a recent major paper. You can find more at his website here

Below are some of the features of the prescription in more detail.

James Hansen's therapeutic procedure

Coal is the key

The chart on the right shows where fossil fuel emissions come from. The share due to coal, after stagnating for some decades at the expense of oil & gas, took off in this century. This is pretty much all about China and India. The fact is, global oil production has been close to static since 2005, and many experts think this is because there's no more easy stuff to be found. Discovery has lagged production for some years, so oil is likely to get more expensive in coming years, whereas coal is still fairly cheap and there's lots of it. The story with gas is not quite so clear, but many experts think this fuel too will hit peak production within a decade or so - notwithstanding the recent promise of "unconventional" sources.

Hansen claims that it will not be safe to push cumulative emissions (total of all historical fossil fuel emissions since 1750) past 500 Gt of carbon. [It's only fair to say other experts think this is too conservative & we could go twice as high. Hansen, however, provides rigorous geophysical reasons for his limit] Of this total, we've already put 370 Gt into the air. To plan a transition, then, we must figure out how we want to spend the remaining 130 Gt.

This leaves no room for more coal, and none for the suite of "unconventional" fuels - tar sands, shale oil & gas, coal seam methane, "heavy" Venezuelan crude, etc ... they have to stay in the ground with most of the coal reserves.

Carbon fee & dividend

Hansen adopts an argument made by a number of economists that the most efficient way to create the market incentives that would propel a speedy transition to non-carbon energy is to levy a "fee" on carbon at its source - coal mine, gas or oil well, import destination, etc - and to return the entire proceeds to citizens in some equitable manner such as a monthly or annual dividend. All current fossil fuel subsidies would be removed as well. This is how it would work:

All fossil fuel dependent economic activities would become a bit more expensive ... so people would be free to figure out how to avoid the cost by using alternatives. That would tip the market in favour of zero-carbon energy and services. It would also favour producers of non-fossil energy and boost innovation. Consumers who managed to save the most would still get their dividend, so the incentive would drive commitment to long term changes in energy consumption - efficiency gains and emission reductions. The size of the fee would be set by political/economic considerations, but it would have to increase regularly until it had the desired effect. No part of the proceeds should be allowed to enter the political arena, where it could be used to promote various interests. The large sums should be treated as a legislated rebate and simply divided equally.

The idea is backed by a compelling practical argument ... up until now, the cost of fossil fuel emissions has been treated as non-existent, or amortised as a future public liability, while the profits go to corporate owners. This might have been excusable before we understood what these costs are - but not any more. It is hardly surprising that the industry has been resisting this new and inconvenient view of its products.

The fact is, as Hansen & others have insisted, that as long as fossil fuels are the cheapest form of energy, we'll keep using them. Once they "pay their way", by assuming responsibility for the damage they cause, we will make better choices - but not before.

Unfortunately, energy will be more expensive in future under any feasible scenario. That's not because "clean energy" is expensive, but because fossil energy for so long was ridiculously cheap. We have lived in an energy bonanza most of the last century, such as the world has never seen - and will never see again. Just because we've grown accustomed to cheap and convenient energy doesn't mean we are entitled to it for ever.

Large scale bio-sequestration of carbon

Even though we can't say precisely what the climate would be like with 400-450 ppm of CO2, we have a fairly good idea, thanks to some clever scientific work. It's not something we would want to leave to our grandkids' grandkids to put up with - not when we still have a chance to avoid it.

That means we must draw down CO2 to a safe level. What would that be? It's the level at which we think Earth would return to energy balance. Hansen has worked hard at this question for some years, and as far as I know, the answer he and his colleagues have come up with is the best one around, and the only one backed by rigorous empirical results. In short, he says, to get the current net forcing to zero would need CO2 at approximately 350 ppm. There's no need to try for more precision. This is close enough to found a good public policy. Older estimates of 450 ppm found in earlier official reports can now be discounted, he says. We can be certain that sustained atmospheric CO2 of 450 ppm would eventually bring the ocean up by tens of metres, and disrupt every ecosystem on the planet with profound consequences.

How do we get enough CO2 out of the air fast enough? Hansen, following researchers who've worked on this for some years, asserts that a really big program of reforestation, together with efficient management of tropical forests, plus a large program of boosting soil carbon can do the trick.

About 20% of all annual emissions come from various land uses. It's estimated that, over the last couple of centuries, forest clearance and arable and pasture conversion has caused the loss of about 150 Gt of carbon from the world's soils to the air - about 10% of this very large reservoir. Some simple changes to farming practices have been shown to reverse this loss. There's also interest in the possibility of converting vegetable residues - crop waste, forestry debris and some specific crops - to bio-char, a form of carbon a bit like charcoal that has some very beneficial effects when it is incorporated into agricultural soils and rangelands. Interestingly, research suggests that the most carbon deficient soils benefit most, and that the potential to augment soils all over the world is huge.

Nuclear energy?

Whether or not to admit nuclear into a clean energy solution is at present a vexed question. It is more complicated than it should be because the whole topic is badly infected with lots of passion & rhetoric and not nearly enough facts. Some people believe we can have a totally renewable energy future (hydro, solar, wind); others don't. Mostly the dispute is about cost.

Saul Griffith, for example, has shown what a truly gargantuan task it would be to build enough solar and wind installations on the timetable required to replace our present energy system, and how much resources it would entail. Various advocates have made a decent case that rich countries like Australia could do it. Nobody has shown that a more or less equitable system could be created for the entire world.

On the other hand, many level-headed energy experts have said we cannot possibly re-create the global energy system without nuclear. This isn't outrageous, because current nuclear plants are a great deal safer than older ones, as well as more efficient ... but better still, there is every reason to think that very high efficiency, ultra-safe integral breeder designs may not be many years away.

There's a short introduction to the integral fast reactor here:

and a longer explanation of why it will be necessary and sufficient here:

A short article on the bio-char concept, and a proposal can be found here:

There's a longer review of the topic here:

Both graphs are from Hansen's long paper, which can be read at the link above. If you want a short summary of its argument, use this link:

Here is Jim Hansen explaining the concept of carbon fee & dividend for the Huffington Post:

Here is Steve Kirsch in the same journal:

So where’s our energy going to come from if we don’t have fossil fuels?

This chart is self-explanatory & it shows what a very big adjustment we need to make to the system of energy supply ....

but - this isn’t a matter of whether it’s possible, just how much we want it. All the technologies we need are there now & only have to be hugely expanded. Our ingenuity will surely supply new sources as we go. If politicians didn’t mind upsetting vested interests, we could be well down the track already.

These numbers refer to the proportion of global energy supply due to each source. They are changing all the time, but can still you give a general idea.


This is not about each of us

"doing the right thing"

We certainly do need to learn how to live with less impact and waste, each and every one of us, but the idea that this will solve the problem is false.

Governments don't mind promoting this message to kid us they are doing everything. The fact of the matter is, laudable private actions are never going to be enough. The problem demands appropriate public policies first and foremost.

Democratic systems have evolved to govern by balancing competing interests. They do this in all sorts of ways, and according to contingent priorities. But, as the American founding fathers knew too well, there is a danger built into this way of doing things - nothing prevents interested minorities from prevailing over the community. Coal producers & other energy interests, being threatened, can concentrate on advocacy much more effectively than the rest of us can; furthermore they are very wealthy. That’s why our policies until now have reflected their interests instead of our grandkids’. But this must change soon.

Guy Pearse, research fellow at the Global Change Institute, University of Queensland, provides an interesting perspective on the ambivalence of governments here:

The case for 100% renewable energy is made here by Beyond Zero Emissions, an Australian research group.

Program for a safe future climate

Peak atmospheric CO2 must be no higher than 450 ppmv

The atmospheric peak must occur not later than 2025

There must be a draw-down of CO2 during the rest of the century to a final stable level not more than 350 ppmv

Fossil fuel burning must be phased out so that net emissions are close to zero before the last decades of the century

A big reforestation and soil management program needs to be started right away & grown throughout the century, to remove CO2.

This prescription isn't perfect