Jeremy Gregory

Sustainability is a term that gets thrown around easily, and it can just as easily bring with it a sense of urgency. Executives feel the need to reduce the company’s footprint, get to net zero, and have it be done in twenty-something years. It’s not a bad goal, but it begs the question of how to actually do it. The path seems direct: Reduce carbon, recycle, or do something else that’s popular. Right?

It’s not always the case, says Jeremy Gregory, executive director of the MIT Climate and Sustainability Consortium. Not everything can be electrified, but it also doesn’t mean there isn’t an option. His work is trying to assess and quantify lifecycle environmental impacts. It often involves big equipment, like planes, trucks and ships, but the endpoint is to help people see all the costs, understand the tradeoffs, and then be able to decide what’s best for them, because there is no perfect solution. As he says, it helps to remember that, “All models are wrong, but some are more useful.”

Filling the Gap
The desire to being carbon-free by 2050 crosses industries. The ongoing hurdle does as well: A company doesn’t have every factor under its control. It can reduce its in-house emissions. It can try to reduce its supplier emissions. It can even put out guidelines and try to reduce its customers’ emissions. But try is the key word because it’s sometimes not a technical change that’s involved but adopting new behaviors.

The desire to being carbon-free by 2050 crosses industries. The ongoing hurdle does as well: A company doesn’t have every factor under its control.

“They go through all of that,” Gregory says, “and in most cases, they won’t be able to get to absolute zero.”

To fill that gap, companies look to invest in voluntary carbon markets to earn offsetting credits. It could be preventing a forest from being cut down or an agricultural project that looks to keep carbon in the soil. These can be “tricky,” because it relies on verifying the results and those results have sometimes been vague because hard data has been difficult to gather. Gregory says that using drones and satellites, which are being explored, could help. The result would create something of loop. The offset estimates could be trusted by businesses and governments. Money would be more easily spent, and the voluntary markets, which need to exist, would be able to exist.

“There are a lot of people who want to invest in nature-based solutions,” he says, “and so we have to make sure that we have reliable measurement methods available to scale it up when there is trust in those approaches.”

Making Big Transportation Sustainable
The researchers and scientists at the consortium also focus on finding solutions for three tough-to-decarbonize heavy transportation areas: aviation, long-haul trucking and maritime shipping. The shared challenge? “They are difficult to electrify,” he says.

The work is not just about bringing down costs or increasing the number of charging infrastructures. It means exploring different technical solutions. With trucking, more voltage and space would be needed and stations would have to be on well-traveled routes. One option is rethinking and reconfiguring warehouses; rather than merely unloading and leaving, a truck could recharge.

With aviation, putting in batteries wouldn’t be sufficient, since they’re heavy and flying is about minimizing weight. Hydrogen fuel could be an answer, but it “would need to really drastically change the design,” for large planes, and that’s decades away, Gregory says.

The most promising short-term solution would be sustainable aviation fuel, which comes from biologically-based sources. The upside is that this “drop-in” approach would require little-to-no change in the engines or airplanes. The problem, as it stands, is that it’s a fraction of the market and cost-prohibitive.

The consortium is looking at what resources could be available to increase the supply and bring down the price. It would probably mean growing specific crops, and it raises the concern what resources it would require and whether they’d compete with existing crops.

Ships are enormous and require a lot of fuel, much of which is carbon-intensive. Hydrogen could be an alternative, ammonia as well. But it leads to a common question that applies to any decarbonization initiative. Does the solution fix the problem or create new ones? As Gregory, says, options exist. Green hydrogen is possible. A hydrogen-powered ship is possible, but it requires making the new technology a priority because it would require time and resources to develop. It hinges back to the importance of knowing the true cost.

“We can do it. It just has to be done in a very intentional way,” he says.

Increasing the Perspective
Gregory says that fundamentally his work is about doing cradle-to-grave assessments, and trying to figure out which product or decision has the least environmental impact? “Everyone is curious about that,” he says. What makes it hard is that while most people are comfortable with cost and performance, they don’t yet have the “carbon literacy” for judging environmental impact. He frames it with a common choice: Paper, plastic or reusable bag? The reusable bag would seem obvious because it’s not thrown away, but …

“The answer is almost always, ‘It depends,’” he says. Is the paper bag made of recyclable materials? Will the materials be recycled again? Is the plastic going to be reused? With a cloth bag, how often is it used? Will it be washed? How often will it be washed, because, as he says, that’s the most intensive and environmentally taxing element.

It’s akin to when he asks his students about what’s the most significant impact of shampoo. Most will say the plastic packaging, but landfill trash isn’t necessarily the biggest detriment. It’s taking the actual shower, because it requires water, heat, soap, towels, along with the production of everything that goes into them.

The above exercise isn’t meant to be dissuasive about finding a solution. It’s just knowing there isn’t the solution. People key in on greenhouse gas emissions and reducing one’s carbon footprint, but there are also factors such as water footprint and air quality metric, which are rarely, if ever considered. The first step is considering them, and, with that fuller picture, it becomes easier to establish priorities, make unavoidable tradeoffs and craft a plan. 

“We’re not trying to come up with the exact amount of CO₂ emissions,” Gregory says. “But rather to help people understand what are the key drivers and what are the actions that will have the most impact.