It’s time for serious study of climate engineering

Although my conservative correspondents obviously disagree, my columns don’t frequently venture off-planet. But today is an exception.

Sadly, we are losing the battle with climate change. If only George H.W. Bush had held to his vow to use “the White House effect” to counter “the greenhouse effect.” If only committed climate crusader Al Gore had managed to win his home state, and thereby the election, in 2000.

If only, after John McCain’s forwardlooking cap-and-trade climate stance during his 2008 presidential campaign, Republicans hadn’t retreated into climate denialism. If only today’s GOP wasn’t in thrall to climate-and-science ignoring Donald Trump.

If only both parties would take their cue from almost 30 Nobel laureates and thousands of other economists and embrace a refundable carbon tax, an eloquent market mechanism to reduce carbon emissions.

If any of those things had come to pass, both the United States and the world would be much further along in battling the climate crisis. But as things now are, the global community doesn’t seem likely to forestall even its worst effects, which climate scientists say requires keeping the temperature from rising more than 1.5 degrees Celsius or 2.7 degrees Fahrenheit above preindustrial levels.

Which is where space might just come in.

There are now several proposals to position a sun shield at a place of gravitational equipoise — a so-called Lagrange point about 900,000 miles from the

Earth — to block or deflect sunlight and thereby reduce the solar radiation warming our planet.

An interdisciplinary MIT team has a scheme at the working hypothesis stage for a massive raft of ultrathin-walled bubbles in space. “Current technologies already allow us to deliver and produce items in outer space, and the concept of inflating and freezing thin films in situ at [the Lagrange point] is possible,” according to a member of the Space Bubbles project team, who said the eventual shield would need to be about the size of Brazil.

Meanwhile, John P. O’Connor, an Andover innovator who possesses a PhD in physics from Yale and a long list of patents, has developed the concept of deploying a sun-shielding honeycomb of hexagons, composed of ultrathin aluminized Mylar stretched across light aluminum tubes. The sides of each individual hexagon would be about 100 feet; when complete, the honeycomb would have a diameter of 350 miles or so.

“The technology exists today to do it,” he said. “Is it easy? Absolutely not.”

Nor would it be cheap. O’Connor’s total cost estimate: $23 trillion, or about $765 billion each year for the 30 years it would take to build. But as he notes, the Green New Deal has a higher price tag. Long-term guesstimates range from $50 trillion to $90 trillion.

The idea itself isn’t new. Roger Angel, a professor of astronomy at the University of Arizona and a MacArthur fellow (read: genius grant recipient), proposed a space-based sun-deflecting approach in 2006. His plan called for an immense flock, as in 16 trillion, of circular sun-deflecting shields, each weighing about a gram and extending about 2 feet in diameter.

In an interview, Angel told me he studied the matter principally to explore and answer questions about its cost, possible materials, and feasibility. “I wasn’t then and I still am not an advocate of this being what we should do to fix global warming,” he said. “I think there are much better solutions now.”

Angel believes direct air capture of carbon dioxide is a better approach, though even if the price comes down from about $500 a ton to $100 a ton, he estimates the cost at some $100 trillion, or $2 trillion a year over 50 years, to restore the atmosphere to its preindustrial level of carbon dioxide.

Like most Americans, I don’t possess the scientific or engineering or budget-estimating expertise to critique plans like these. But two things do seem to me to be true.

First, unless something changes in a

A space-based sun shield seems far less invasive than, say, seeding the ocean with iron-rich particles to trigger blooms of carbon dioxide-absorbing phytoplankton or dispersing substances like sulfuric acid into the stratosphere.

relative hurry, we are going to have to resort to geoengineering.

Second, a space-based sun shield seems far less invasive than, say, seeding the ocean with iron-rich particles to trigger blooms of carbon dioxide-absorbing phytoplankton or dispersing substances like sulfuric acid into the stratosphere.

Is this all real or does it tend toward pie in the sky? We don’t yet seem to have an official or even quasi-official effort to evaluate various proposals. But as the Globe’s Sabrina Shankman recently reported, scores of scientists wrote an open letter calling for careful research on various modes of solar radiation modification. That has kicked off a controversy because of worries such an effort could lessen the sense of climate urgency.

Those are understandable concerns, certainly, but the time has come to get a better idea of what’s really possible — even if the ideas sometimes seem a little out of this world.