The Rate of Change: July 8, 2019
We have too many fossil-fuel power plants to meet the 1.5° C target
Last year, we were given a carbon budget. This is the total amount of carbon dioxide that we can add to the atmosphere in the foreseeable future, to cap global warming to a few degrees Celsius. Think of it as the remaining balance in our carbon bank account.
So what’s our current balance? For a 50-50 chance (essentially a coin toss) of capping global warming at 1.5°C, our carbon budget is 580 billion tons of carbon dioxide. For a 2 in 3 (or 67%) chance of hitting this target, our budget is 420 billion tons.
How long does this buy us? Every year, we’re spending about 42 billion tons of carbon dioxide from our carbon bank account. It isn’t hard to do the math. Just divide 580 by 42 (or divide 420 by 42 if you want to play it safe). That’s how many years it’ll take us to spend our entire budget, assuming things don’t change. If you average these answers, you get 12 years.
In other words, at our current rate of emissions, we’re set to exhaust the 1.5°C carbon budget in a little over a decade.
And it gets worse. An important new study published last week in Nature argues that we’ve already committed to overspending this carbon budget. That is, if all the power plants, factories, vehicles, buildings and appliances in use today keep operating as long as planned.
Every coal or natural gas power plant that we build is like signing up for a new monthly payment plan with our carbon budget. By adding up the future payments for all the stuff that we’ve already signed up for, this study teaches us that we’ve already maxed out the 1.5°C carbon budget.
Stephen Leahy reports in National Geographic:
“Our study is dead simple,” said Steven Davis of the University of California, Irvine, a co-author of the paper published in Nature. “We wanted to know what happens if we don’t build any more fossil-fuel-burning stuff as of 2018.”
To answer that question Davis and colleagues looked at all the emissions from electricity, energy, transport, residential, and commercial infrastructure as of 2018.
[…]
Add up all those lifetime emissions from existing infrastructure, Davis and his colleagues estimated a total carbon commitment of about 658 billion metric tons of CO2. That’s 78 billion tons above the maximum the Intergovernmental Panel on Climate Change (IPCC) says can be emitted to have a better than 50 percent chance of stabilizing temperatures at 1.5°C of warming.
Read more in National Geographic. The article gives us the main takeaway:
To limit warming to 1.5°C., not only should no new fossil-fuel-using infrastructure be built, ever again, some existing power plants need to shut down early—and yet today many new power plants are under construction or planned.
A second takeaway is that it is basically impossible to meet the 1.5° Celsius target by reducing emissions alone. To meet this target, we will also need a very serious push for ‘negative emissions’, i.e. solutions & technologies that suck carbon dioxide out of the atmosphere, in addition to keeping it from getting there in the first place.
Another option is to abandon the 1.5° Celsius target, and aim for a 2° Celsius target instead. That buys us about a few more decades to ramp our fossil fuel consumption down to zero.
The difference between 1.5°C and 2°C might not seem like a big deal, but it is. Here’s what we can expect with an additional half a degree of warming:
Warmer oceans take a bite out of our carbon budget
When it comes to climate science, small numbers can have outsized consequences. Here’s a recent example. The UK Met Office just released its updated measurements of ocean temperatures (known as the Hadley Sea Surface Temperature data, or Hadley SST for short). With this update, they report that “the world’s oceans have warmed by around 0.1C more than previously thought since pre-industrial times.”
A tenth of a degree doesn’t sound like a lot, but here’s what this change implies:
Carbon Brief estimates that the revisions to the Hadley SST record would reduce the global “carbon budget” remaining to limit warming to 1.5C by between 24% and 33%, depending on how the budget is calculated. A smaller budget would mean humanity has fewer carbon emissions it can still emit before committing the world to 1.5C of global warming.
At the current rate of emissions, this would mean the 1.5C budget would be used up in 6-10 years – rather than 9-13 – potentially making the target even harder to achieve.
Read more at Carbon Brief. (via @GretaThunberg)
Doing the Math On Trees
You might have come across recent stories claiming that reforesting land is “our most effective climate change solution to date”. These articles are based on a recent study published in Science. It’s worth pointing out that there are a few caveats to this idea.
First off, no one doubts that restoring natural forests (as opposed to planting commercial crops) is an essential part of the climate solution. Even if we ignore the benefits to ecosystems and biodiversity (which we shouldn’t), forests are still the best way to remove carbon from the air. (Fun fact: according to a study in Nature, converting land to forests traps 42 times as much carbon as growing commercial plantations.)
However, it’s perhaps overstating the case to call forestation “our most effective climate change solution to date”. Here’s why:
Trees take time to grow (and trap carbon), on the order of centuries, and we only have decades before we use up our carbon budget for 1-2° C of warming.
The study makes it seem that restoring forests can store ~200 billion tons of carbon, which would add a significant amount to our carbon budget. However, half of the carbon that trees absorb returns to the atmosphere, and only half remains trapped on land. So we should divide that number by two.
The study describes planting trees over a global area comparable to the land area of the United States. While they make the case that finding this much space will theoretically be possible, it’s definitely a tall order.
Let’s do a little thought experiment. Say we manage to reforest enough land to effectively trap an additional 100 billion tons of carbon from the air, but our emissions continue as usual. What does this buy us?
To convert a weight of carbon to a weight of carbon dioxide, we multiply by 44/12 or 3.67, which is the molecular mass of CO2 / molecular mass of C. So we’re talking 3.67 × 100 = 367 billion tons of carbon dioxide being absorbed by trees (and it’ll take about a century for us to see this payoff). Meanwhile, if our current rate of carbon emissions continues unabated, we’ll offset this benefit in 367/42 ≈ 9 years.
The punch line: even a well-coordinated, global-scale effort at restoring forests will be too little too late, unless also accompanied by a steep reduction in carbon emissions.
Alice Bell points us to an excellent critical summary of this study.
Are parts of India becoming too hot for humans?
Experts at the Massachusetts Institute of Technology (MIT) say that even if the world succeeds in cutting carbon emissions, limiting the predicted rise in average global temperatures, parts of India will become so hot they will test the limits of human survivability.
"The future of heat waves is looking worse even with significant mitigation of climate change, and much worse without mitigation," said Elfatih Eltahir, a professor of hydrology and climate at MIT.
Read more by Shekhar Chandra in CNN. The article summarizes research published in the journal Science Advances in 2017.
69% of people in the US accept that global warming is real, and 55% understand it is human-caused
It’s worth reading the key takeaways from the recent Yale report on Climate Change and the American Mind.
About seven in ten Americans (69%) think global warming is happening. Only about one in six Americans (16%) think global warming is not happening. Americans who think global warming is happening outnumber those who think it isn’t by more than [..] 4 to 1
Interestingly, only 1 in 6 people in the US are aware of the extent of the scientific consensus on global warming. Climate journalist David-Wallace Wells summarized these findings as “many Americans believe warming is a very big deal even though they think scientists aren't so sure.”
The case for individual responsibility
In Popula, Maria Bustillos offers a compelling counter to the narrative that individual action is ineffective in combating climate change. Her views resonate with me.
For a decade or more there has been a cottage industry in telling people that individual action is meaningless in the face of the overwhelming force of climate change. Plane rides don’t matter, eating meat doesn’t matter; 100 companies are causing 71% of the emissions and it is they who are the problem; only governments acting in concert have the remotest chance of arresting the disaster. And so on.
[…]
There is no way to achieve collective action without individual action. Collective action doesn’t fall off a tree, it is made up of countless individual acts that turn into conversations, writings, meetings, plans. Individual actions are the only material from which collective action can be made, and to suggest that individuals are helpless and somehow just don’t matter now, in the current emergency, at a time of rising confusion, anger, hopelessness and dread, is nothing short of enraging.
Near the end of her piece, Bustillos links to an academic article that analyzes why people believe that individual actions are ineffective in combating climate change. Among other things, that article argues for adopting a more quantitative approach to thinking about our climate impact, which is an idea I plan to explore in future newsletters.
More great reads
>> Akshat Rathi highlighted this piece by Clifford Krauss in the New York Times. Last year, US oil and gas production both had the largest annual growths of any country in history. However, the stock prices of these companies tell a different story.
>> Akshat also produces an excellent climate newsletter that you should check out.
>> The Guardian reports that one of the world’s largest insurance companies has pledged to stop insuring coal power plants. (via Ritwick Ghosh)
>> Climate change is a key driver of the US border crisis. By Jonathan Blitzer in the New Yorker. (via Leah Stokes)
>> Last month was the hottest June ever recorded.
>> On Thursday, Anchorage, Alaska recorded a temperature of 90 degrees Fahrenheit (~ 32 Celsius), a record high. Mike Baker reports in the New York Times.
>> It turns out that planes are even worse for the climate than we thought. Michael Le Page reports in New Scientist.
>> An informative & thoughtful conversation on The Opportunity and Challenge of Nuclear Energy with a former US Deputy Secretary of Energy, over at the Columbia Energy Exchange podcast.
>> Looking for more great stories on climate change? The responses to this thread by Dr. Katharine Wilkinson are an excellent place to start.
That’s all for this week, see you next time!