In its lifetime, Boston Common has seen grazing cattle, public hangings, and protests against slavery and wars. It has seen visits from the Rev. Martin Luther King Jr. and Pope John Paul II and the everyday gatherings of families and friends. And someday — depending on the choices made in the next few years — it could see the rising waters of the Charles River, as sea levels rise from climate change and swallow the historic landmark.
As world leaders prepare to gather in Glasgow for the next major round of international climate talks, they will be discussing the difference of degrees, attempting to bring the path the world is currently on — which would result in 3 degrees Celsius of warming above preindustrial temperatures by the end of the century — in line with the goal of the Paris Agreement, which is half that, or 1.5 degrees Celsius of warming.
The difference between those two numbers may seem insignificant, but as research released Tuesday shows, it has a very real consequence — such as whether the Common will be underwater or not.
“What we do in the next 10 years will matter for 10,000 years,” said Benjamin Strauss, chief scientist of Climate Central, an independent organization of leading scientists and journalists that released the research. “I don’t think in the history of humankind there’s been a time when we’ve been able to understand what a large impact our current decisions and actions could have on so many generations to come.”
In hundreds of images and an interactive map, Climate Central has used the latest science on sea level rise and climate change to show the difference between how Boston and other coastal cities around the world will fare at 1.5 degrees Celsius versus 3 degrees Celsius over the next 200 to 2,000 years. Three of those locations show how high the stakes are in Boston. What the images make clear, said Strauss, is “the zone we can save.”
Boston under projected sea levels
The project aims to put into focus the consequences of the Glasgow talks. A recent report from the United Nations found that the commitments made by nations leading into the talks are not nearly enough to keep warming to 1.5 degrees Celsius, but rather put the world on a “catastrophic pathway” to 2.7 degrees Celsius of warming, according to UN Secretary General António Guterres.
Already, the world has warmed 1.1 degrees Celsius above preindustrial time. The amount of carbon in our atmosphere that has led to that warming is enough to cause an average of 6.2 feet of sea level rise around the world — and that doesn’t take into account any emissions after 2020, according to Climate Central.
In some parts of Boston — which Strauss said is uniquely vulnerable due to its high volume of coastal development — the sea level rise already will put some areas underwater in coming centuries. How much worse it gets will depend on whether warming is held to 1.5 degrees Celsius or is allowed to continue to 3 Celsius.
The Edward W. Brooke Courthouse near the Haymarket T station shows just how bad it will get. According to the Climate Central projection, even at 1.1 degrees Celsius the area around the courthouse will be underwater. At 1.5 degrees Celsius and 3 degrees Celsius, those waters only rise higher.
EDWARD W. BROOKE COURTHOUSE
A half-mile away, 3 degrees Celsius of warming could bring water up to the Old North Church. Warming of 1.5 degrees Celsius would still put much of the waterfront and the streets around Battery Wharf underwater.
OLD NORTH CHURCH
If climate change is held to 1.5 degrees Celsius, rising seas would affect land today inhabited by 510 million people. At 3 degrees Celsius of warming, that number would reach more than 800 million people — or 10 percent of the global population.
The risks are particularly acute for low-lying island nations, as well as cities around Asia, which sea level rise projections indicate could be almost entirely underwater.
“If we’re going to limit warming to the level that scientists say is closest to safe — 1.5 degrees Celsius warming — it means the world has to cut its carbon emissions in half by 2030,” said Strauss. “The good news is, we know how to do it — we have the technology. It’s just a matter of actually deciding to do it.”
Correction: An earlier version of this story incorrectly stated the age of the Edward W. Brooke Courthouse. It is 22 years old, built in 1999.