Can We Stay Within Our Carbon Budget?

Even though I grew up in a poor family, I started getting a very small allowance when I was about 10 years old.  I think it started at 20 cents per week.  It wasn’t much, but it was mine.  Soon I started saving some of it each week so I could get the toy truck I wanted.  Before long I had what was essentially a simple budget that told me how much I could spend in any time period if I wanted to meet my longer range goals.¹

A carbon budget tells us the cumulative amount of carbon dioxide humanity can emit (primarily through the burning of fossil fuels) and still keep global temperatures from rising more than a certain amount.² If we burn so much coal, oil and gas that we go over budget, then temperatures will rise more and true climate disaster will be inevitable.

The UN Intergovernmental Panel on Climate Change (IPCC) report issued last fall makes it clear that we need to keep the global temperature increase to 1.5°C above pre-industrial levels.  If global temperatures rise 2°C or more, then the levels of heat fatalities, hunger, wildfires, catastrophic storms, sea level rise, disease, and deadly conflicts will be disastrously greater.

Our Carbon Budget and Our Current “Spending”
The amount of greenhouse gases humanity can emit and still stay within the 1.5°C limit is our carbon budget.  Scientists have calculated that amount.  It’s roughly 420 gigatons of carbon dioxide (GtCO2).³  That’s not 420 Gt per year, that’s 420 Gt total, forever (at least until 2100 and probably for all of history).  The world is currently emitting about 42 Gt of carbon dioxide into the atmosphere each year.  At our current rate we will use up our entire carbon budget in less than 10 years!

The IPCC says we can still make it, if we cut our greenhouse gas emissions roughly in half by 2030 and to zero by 2050.  As David Roberts at Vox writes, “To give developing countries more room, wealthy developed nations like the US should ideally decarbonize faster.  To do that, the US will have to phase out all fossil fuel use as fast as it conceivably can.”⁴

Good News
The good news is that the technology exists to make a rapid and full transition to renewable sources of energy – primarily wind and solar – in time to stay within the carbon budget.  The problem is that the political will to make this transition in time doesn’t yet exist.  This is where we all come in.  See below for some recommendations.

 We must have a just transition for workers in the fossil fuel industry that provides them with new training, transitional income, and new high paying jobs. A comprehensive approach like the Green New Deal can insure that equity for all is central to this transformation.

One Implication
There is more than twice as much coal, oil and gas in mines and wells that are already in operation than our carbon budget allows.  The companies that have developed these resources are going to need to leave more than half of them in the ground.  The obvious implication is that there is no room for new fossil fuel development.  All exploration for new underground sources of gas and oil, efforts to open up new areas to drilling, and plans for new wells and mines are morally bankrupt. If realized, they will imperil humanity and millions of other species.

I’m writing about the carbon budget because I think keeping this perspective in our minds can guide what we do both individually and collectively.  At the individual or family level lowering our personal carbon footprint makes a difference – taking short showers, washing our clothes in cold water, driving and flying less, turning our thermostats down in the winter and up in the summer, etc.  See “The 35 Easiest Ways to Reduce Your Carbon Footprint” from the Earth Institute at Columbia University.⁵

What Can We Do Together?
However important, personal actions alone will never keep humanity within our carbon budget.  We must act collectively.  I recommend everyone meet with your state representatives and your municipal officials monthly.  They either have office hours or will make appointments.  Whether they are already advocating for climate mitigation or are staunchly opposed, they need to hear from you often how important this is to you.   Even if you’ve never been political, go see them regularly. Go alone or with a friend the first time, then add one more person to your group each time.⁶

The city of Chicago just passed a resolution committing it to 100% green energy by 2035, and all electric busses by 2040. School districts from Newton, Massachusetts to conservative Orange County, California are installing solar panels over their school parking lots.  Nevada has a new law requiring their electric utility companies to get 50% of their power from green sources by 2030 and 100% by 2050.  The small town of Amherst, Massachusetts adopted legislation requiring all new public buildings be 100% net zero – making as much energy as they use each year.  Your state, your municipality could do all of these things, and more, but only if we all insist our elected officials and candidates become climate champions.

It will take all of us to see that we don’t overspend our carbon budget.

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1. In case you are wondering, I did eventually save enough to buy the red truck I wanted as a youngster.
2. There are more complex carbon budgets that calculate methane emissions separately, and take into account other sources of carbon emissions, and carbon capture and storage.  They are important for some decisions, but none of them significantly change either the numbers or the conclusions of this post.  Here I’m limiting our discussion to the carbon budget for fossil fuels.  Carbon dioxide is not the only greenhouse gas that we emit, but the numbers for other emissions are usually reported in CO2 equivalents.
3. This is the number that the IPCC says will give us a 66% chance of staying below 1.5C temperature rise. The number is different in different reports depending on what assumptions are made about methane emissions, how much we will be able to increase carbon sequestration through agriculture and planting of trees, and other variables.  [Edit added 10-10-19: 420 Gt was the carbon budget left on Jan. 1, 2018. The amount is now down to less than 350 Gt !]
4. https://www.vox.com/energy-and-environment/2019/5/30/18643819/climate-change-natural-gas-middle-ground
5. https://blogs.ei.columbia.edu/2018/12/27/35-ways-reduce-carbon-footprint/
6. You don’t need to be an expert.  Tell them what you care about most in the face of the climate crisis – the children of future generations, your favorite beautiful spot.  Share ideas from this post, or give them a copy of it.  It’s their job to find the experts and work out the details.