The reason for this note is that discussions of climate change have splintered into so many directions that the subject appears more daunting than it ought to be.  Neither the current status nor the path to success is actually hard to see.  The main things we need are commitment and a real plan.

1. Current status

– Evidence for climate change is clear and unambiguous.

The increase in global temperature levels goes back decades, as shown in the following chart (Temperature Anomaly just means the temperature increase over 19th century levels).

Further the relation of temperature and CO2 in the atmosphere is unmistakable (see the straight line below) and pushing up inexorably toward the identified 1.5 ºC danger zone:

Scientists have even demonstrated (using isotopes of carbon) that the increased carbon dioxide in the atmosphere is due to burning of fossil fuels, not some natural process.  Arguments to the contrary have been largely funded by the Koch organization or the oil companies themselves and typically involve doctored data.  Accusations of conspiracy have been debunked, but are still repeated by interested parties.

– Problems are already happening.

There are two kinds of examples.   For temperature alone, as the first chart showed, we’re continuing to set new records for average global temperature.   The effect on sea ice has been dramatic, and farmers are becoming well-aware of changes in growing seasons.

Individual catastrophic events are harder to pin down, just because it’s hard to develop statistics around rare events.  However, scientists have been able to work through the statistics to show the extent to which extraordinary storms, such as hurricane Harvey, were made worse by climate change.

– Role of climate models.

We don’t need climate models to say there is a problem.  We do need climate models to assess specifically what is going to happen.  For example, we can see that glaciers in Greenland and Antarctica are melting, but we need to figure out how quickly this can happen and what the effects will be on weather and ocean currents.  Since the earth hasn’t been here before (i.e. rapid C02 increase like this has never happened), we have to try to figure it out.

A particular concern is that climate change feeds on itself to accentuate the effects of CO2.  An example is melting of permafrost in the arctic.  That releases methane, which is also a greenhouse gas and adds to the increase expected with CO2.  Climate models are extremely detailed to deal with such effects.  The modeling work is supported by a global effort to get data on what is happening now.  This is a major effort by many independent researchers worldwide to get the best possible handle on what’s coming.

– It’s going to get a lot worse unless we start acting now.

An important fact to be emphasized is that carbon dioxide in the atmosphere just adds up.  So even if we stabilize global production of carbon dioxide, things will just get worse as we add to the total.  For a few years 2014-2016 it looked like CO2 production was stabilizing, but then the trend turned worse, and last year accelerated it.  Here is the current chart.

As we just noted, even a stable value of CO2 emission means things are getting worse, because it is the total amount of CO2 in the atmosphere that drives temperature change.  The stable value was attractive, because it seemed to indicate that CO2 had finally peaked and might start to decline.  And the decline might mean the total CO2 could be bounded.  We’re now back to worrying about the peak, with no idea how bad things will get.

Scientists have given us a so-called carbon budget—the maximum amount of CO2 we can add to the atmosphere and still escape dangerous, irreversible changes.  Every bit we add counts against the budget.  We have to find a way to get carbon dioxide production down toward zero, and things will continue getting worse until we get all the way there.   According to the last international climate study, CO2 production needs to drop 45%  by 2030 and reach 0 by 2050 if we want to keep the temperature increase under 1.5 ºC.

– Can’t we just pull the carbon dioxide back out later?

There is currently a lot of work in progress on how to capture and store carbon dioxide.  For now, capturing carbon dioxide even in exhaust flues is expensive—it can double the cost of electricity from a coal power plant.  Pulling it out of the air is substantially harder.  Further some effects, like movement of glaciers, are hard to stop even if we pull out the carbon dioxide later.  Sea level changes are irreversible.

Earliest use of this kind of technology would be for flue-based solutions in particular industries.  That’s getting cheaper, but it’s no miracle solution.  Large-scale pulling carbon out of the air is not yet available, and the cheapest estimates for a worldwide solution would cost on the order of 10 trillion dollars annually.  Nonetheless, current climate models assume that some use of this technology (expensive or not) will be needed if we are to keep the temperature increase under 1.5 ºC.

– What about geoengineering?

This approach, which gets sporadic publicity, involves adding chemicals to the atmosphere to block the sun—cutting temperature by putting the whole world in the shade.  A number of different substances have been investigated to do this, and any of them would need to be constantly injected into the atmosphere under supervision by some international body.

As an approach this is much cheaper than carbon capture, but it is regarded as a dangerous last resort even by the people who do the research.  All photosynthesis worldwide would be affected. The closest natural phenomenon, the Mount Pinatubo volcanic eruption in 1991, resulted in a worldwide drought.  It does not address acidification of the oceans, which would continue to disrupt life in the seas.  Further it is a time bomb, as carbon dioxide concentrations would continue to build up, so that the shading and its effects would have to keep increasing, and any interruption would be catastrophic.

The bottom line is that there is no silver bullet here; we have to get off burning carbon.   However it’s worth pointing out that this is NOT a death sentence (as we’ll see) and it is also NOT committing us all to a grim world of scarcity.  Even today people buy Teslas because they like them—among other things they’re performance cars—not as sacrifices for the good of mankind.  That’s the right way think about the whole transition.

2. What to do about it

To understand what we need to do about climate change, we first have to think about the kind of world we would be going toward.

A point worth emphasizing is that the future is electric.  If we’re getting off fossil fuels, we’re not going to have people burning stuff all over the place.  So we will be generating power by suitable technology (more on that in a minute), and electricity is the means of storing and distributing that energy.  All renewable sources today generate electricity as the common currency of power.

Since the electric grid is the core for what we need to do about energy, we have two primary tasks:  strengthening the electric grid and getting all users of energy on that grid.  Each needs to be discussed separately.

– Strengthening the electric grid

This is about generating and distributing power.   We of course need a grid that is reliable and safe, but for climate change we’ll need more.  There will have to be considerable growth in electrical power generation (since we’re taking on new roles), and we will want to optimize opportunities for renewables even in the near-term.

At present there are ongoing activities to strengthen our current patched-together national electric infrastructure, but these are long-term projects and not primarily driven by climate change.  Power generation is largely a per-state matter and is quite literally all over the map.  For climate change we have benefited from the near-term improvement of substituting natural gas for coal, but there are still many coal plants and nothing says we have optimized opportunities for renewables.  Ideally we should have a nation-wide plan for growth and modernization that would allow renewable power to be generated where appropriate and used wherever needed.

It’s also worth saying something about the longer-term picture.  Ultimately this is not a story about scarcity and conservation; it’s about alternative power.  Renewables will improve, and there will be other significant new sources of power.  Fusion power in particular has been slow to develop, but should be taken seriously.  It has had a recent impetus with higher-temperature superconductors (for the magnets that contain the fusion reaction), and current international projects target 2033 for a demo system and 2050 for commercial system deployment.  Initial systems will be heat-based, like conventional power plants, but later generation systems may generate electricity directly —a mind-boggling concept.  (Interestingly, this may even involve mining on the moon.)  We have a near-term job to do in saving the planet, but there’s no reason to fear we will ultimately lack for power.

– Making electricity the universal power source

The point of departure here is the following chart showing energy use by sector and energy source.  Our task is a prioritized migration to renewably-generated electricity in all sectors, with the maximum possible bang for the near-term buck.  In this transportation is an obvious target. It is a large consumer of energy (28% of US energy usage) with negligible current penetration of renewables.  Electric cars can be a big win.

Given the complexity of energy usage overall, the single most important step to encourage migration is to stop pretending that carbon dioxide production is free, i.e. to stop subsidizing the fossil fuel industry.

We can be pretty specific about what CO2 costs us.  We are rapidly reaching the point where each new ton of CO2 in the atomosphere is a ton that will have to be removed.  The cheapest estimates of what it takes to remove CO2 from the air (average of upper and lower bound estimates) is $163 per ton.  Multiply that by the US annual production of CO2 = 5.4 B tons, and the silent subsidy to the fossil fuel people falls out as $880 B annually.  That’s no small distortion of our economy.  Essentially a trillion dollars a year.  Another way to say the same thing (when you work out the math) is that every gallon of gasoline sold gets a silent subsidy of $1.47.

The usual approach to this subject goes by the name of a carbon tax, but that’s actually a misnomer.  A tax is money collected to fund some government activity, and that’s not the point here.   We’re stopping a government-funded subsidy of products that produce CO2, and any money raised should be used to mitigate the effect of fuel price increases on the population.

Because raising fossil fuel prices is regressive, balancing costs and benefits is tricky and has led to voter rejection (spurred by massive Koch campaign spending) of several carbon tax proposals.  (The yellow-vest protest in France was from something worse, a budget-balancing regressive tax masquerading as a climate measure.)  The magnitude of the silent subsidy is such that it is necessary to get this right.

One example proposal worth discussing is the Carbon Fee and Dividend from the Citizens Climate Lobby.  They start with a low fee of $15 per ton of generated CO2 at fuel production or port of entry, but raise the value $10 per year afterwards.  That money gets returned per adult with an added allowance for children.  The gradual increase is in part a low entry but it also allows for increasing maturity of competing technologies.

That proposal is now a bill in Congress, and there was a recent endorsement by a number of economists and other public figures.  It may or may not become part of the Green New Deal from the Congressional Democrats.  One way or another carbon pricing is so fundamental it just has to be fixed.

3. Outline of a plan

The energy use chart from the last section says a lot about how this has to work.  Going down the chart, we can say the following:

– Transportation

Thus far this sector has had virtually no penetration of renewable energy sources, so its importance cannot be overestimated.   The only alternative is electric power, so we need incentives to finally get a non-trivial market share.  Carbon pricing will help, but we may need more. We’ve had incentives in the past to help electric car makers get into business.   Now the issue is the continuing cost of carbon.

– Industrial

The ongoing migration to natural gas shows the price sensitivity of this sector.  That trend toward gas should continue, and we need to start more movement onto the electric grid.  Carbon pricing should help here too, and there should be active discussion with industry to determine what form it should take.  Flue-based CO2 capture may also be appropriate in some cases.

– Electric power

We already noted the major contribution from this sector in the conversion from coal to natural gas.  That should continue with the non-trivial number of remaining coal plants, but we still have to get to renewables.   Everything that happens in this sector should flow out of a national plan for evolution of the power grid, as discussed before.  Coal plants and also gas-powered plants may be supplanted by renewables elsewhere.

– Residential and Commercial

We should recognize that this sector is significantly smaller and with many subsectors to be considered.  The conversion to natural gas is already well-underway and the remaining petroleum sectors (e.g. New England) may not be easy to change.  So we need to map out conversion to electric or possibly even flue-based CO2 capture.   The first step is a more detailed plan.

We also need to call out the need to support research, as it is an unavoidable part of the picture.  That applies both for new energy sources and storage, and to the various activities underway to understand climate change and how we will have to adapt.

4. International coordination

Thus far our discussion has focused on the US, but we’re only one piece of the puzzle.  Despite the nationalist rhetoric, there is only one atmosphere for everyone.   Helping other countries helps us, and poorer countries have fewer resources.  The following chart underlines the importance of that effort—the “others” are becoming the biggest piece.

There are actually two points to be made.   First, the Paris Agreement included an initial arrangement between rich and poorer countries, so that progress could be made.  That codified a fund (trashed by Trump) to help poor countries meet their targets.  However the issue will continue to be contentious, and one way or another we will have to contribute.  The just-completed Madrid meeting ended without agreement.

Second, our contribution may turn out to be more than just money.  Other countries will have energy use charts that won’t look anything like the one we’re been considering.  They may need different forms of technology to support different evolution plans.  We should use our resources to see what can be done.

In the past the US recognized a responsibility to lead this process.  With the US now firmly committed to cheating, it’s hard to keep things going.

The world needs our contribution to leadership. That means it is doubly important to put our own house in order .  We need to know where we’re going for ourselves, and so that we can help the rest of the world in this effort to preserve our common future.