Nature v. Tech

Competing for climate change dollars

Photo by moreau tokyo on Unsplash

In the last couple of years, companies such as Microsoft and Meta have been shifting their climate change support to high-tech start-ups seeking to collect airborne carbon dioxide in warehouses. Before then, they were using some of these funds to help protect and restore forests, nature’s longtime carbon picker-uppers.

Ecologically, this is bad news. Forests do a lot of heavy lifting when it comes to moderating and adapting to hot climates, now and in the geological past.

Now, the world’s forests annually take up about a third of the carbon dioxide released by humanity’s burning of forests, coal, oil and gas. They do so despite the ongoing deforestation for logging and cattle ranches, despite wildfires and record-breaking heat. They could do even better if we weren’t hacking away at them for palm oil and beef imports.

In the geological past, warmer climates consistently led to the expansion of global forest cover. This was true during the interglacial warm periods between the recurring ice ages of the past 2.6 million years. It held during warm epochs of the past 35 million years, before ice built up in the Artic.

Drawing attention to this planetary greening under warm conditions runs the risk, in some minds, of feeding climate change denial. That’s probably why scientists stopped using the phrase “the greenhouse effect” to describe climate change decades ago. Acknowledging that our hotter Earth was an “Emerald Planet,” as one natural scientist called it, might give the mistaken impression we can keep burning coal, oil and gas.

That’s a real risk. However, ignoring the greening that generally comes with higher temperatures runs a bigger risk, in my opinion, of not giving our forests their full due as allies in helping us moderate and adapt to climate change.

So let’s put posturing aside and consider what really happened during these hotter periods of the past.

Global warming brings on many social woes, as I explained in my University of Arizona Press book Life in the Hothouse: How a Living Planet Survives Climate Change. Stronger hurricanes, bigger floods, higher seas, hotter droughts and more intense heat waves and wildfires come with higher temperatures.

But losing the global forest cover is not something to expect from a warming climate alone, based on past evidence and modern observations.

Even during hothouse periods of the more distant past, when ice-free poles created a watery planet with seas several hundred feet higher than today’s oceans, forests thrived and expanded. For example, tropical forests ringed the planet while the predecessor to dawn redwood grew tall and wide near the poles in both the Arctic and Antarctic.

In fact, drought intensified during the recurring ice ages of the past 2.6 million years. Cold, windy drought. And global vegetation shrunk. Ice sheets cyclically expanded, burying northern forests, while tropical forests largely transformed to grasslands or savannah.

This take is based on thousands of paleorecords—evidence revealing the climate and ecology of the past—such as ancient pollen, tree rings, petrified wood, fossils with leaf imprints, and ocean sediment composition. Using this information and other data, researchers pieced together a picture of global forest cover during past climates warmer than today’s.

It took scientists a while to accept that warmer climates are wetter. Like many people today, scientists of the 1960s figured a planet with more heat would face widespread drying. But the evidence in the ocean sediments, pollen deposits and later, ice cores, all pointed in the same direction: interglacial warm periods featured wetter climates than glacial periods.

It makes sense physically. Warmer temperatures spur on higher evaporation rates from the roughly 70 percent of our Earth’s surface covered by water. And what goes up must come down. Within a week or so, the evaporated water precipitates as snow and rain.

Other evidence also revealed warmer temperatures initiated global forest expansion, while cooler ones caused forests to contract.

It’s not as counter intuitive as it might first appear. Almost by definition, warm climates feature higher levels of heat-trapping gases—especially carbon dioxide—than cooler ones. And trees build their tissues out of water and carbon dioxide. By dry weight, trees are half carbon—all of it pried away from carbon dioxide.

So adding more rainfall and carbon dioxide along with enough sunshine and, ideally, non-freezing temperatures, is a recipe for tree growth.

That’s why tropical rainforests are so crucial to our modern climate change challenges. They take down massive amounts of carbon dioxide. The foggy rainforests of the Pacific Northwest similarly stand as massive reminders of how much carbon trees can hold when non-freezing temperatures combine with humid conditions.

How do fires fit in? Well, it’s true higher temperature boost wildfire hazard under dry conditions. But climate change can’t take the full blame for our modern raging conflagrations.

For one thing, we’ve restricted the formerly widespread but low-to-the-ground cultural burning of tribal nations and other Indigenous peoples. For another, we’ve logged the biggest, most fire-resistant, trees out of U.S. forests—leaving behind the smaller trees that lift fire high into any remaining canopy. What’s more, we’ve diverted rivers that would have watered trees.

Wildfires happen. They can even be nature’s way of clearing the area for more suitable vegetation as climate shifts. But warm times in general do not increase the global area of burned landscapes bereft of trees. Under natural conditions, forests soon regrow.

Perhaps concern over wildfires has put companies off supporting forest protection. Current standards for crediting forests with growth tend to ignore fire damage—a situation that harms credibility. That needs adjusting.

Still, perhaps it’s predictable that Tech Bros would favor tech solutions over nature-based ones.

When Microsoft Corporation released a statement in 2023 declaring it would no longer support tree planting and forest protection but instead shift to “direct carbon capture,” it didn’t lay all its cards on the table. Left unsaid was that Microsoft owner Bill Gates owned shares in some of the companies offering artificial carbon-collecting services, such as Heirloom Carbon Technologies.

With the Microsoft agreement and a $53 million investment from Gates and a few others, Heirloom secured a slew of other investments totaling nearly half a billion dollars by mid-2024, according to Louisiana Economic Development. Its June 24 post announcing a pending Heirloom facility in Shreveport noted the start-up also signed deals with JPMorgan, Shopify, H&M, Autodesk, and Meta.

These tech upstarts usurping the jobs of trees come with data on every gram of carbon dioxide they remove. It’s almost as simple as measuring weight change. The compound they use, typically limestone based, collects carbon dioxide (adding weight) and then releases it upon exposure to temperatures hot enough to melt bronze.

But they likely won’t tally into their climate change calculations the heat released from their open-air warehouses. They won’t measure the environmental cost of mining the limestone and metals needed for operations. They won’t account for the value of the trees felled for construction or the plants and animals displaced by their carbon-collecting warehouses. And they won’t count the energy and materials it took to build the steel contraptions and heat the compounds to 1,650 degrees Fahrenheit.

Even if they use renewable energy, as promised, it generally takes mining of materials to create renewable energy sources. And now they’ll be competing for those renewable sources with cities and individuals also seeking to reduce their reliance on coal, oil and gas.

These warehouses won’t take down more carbon dioxide than promised, as forests often do. They won’t necessarily store carbon safely, in a way that benefits nearby life forms. And they certainly won’t provide wildlife habitat or any of the forests’ other vital functions helping the planet and its people adapt to a changing climate.

Instead of heating their surroundings, trees cast shade and evaporatively cool the air. Their contributions can bring local temperatures down by 10 degrees Fahrenheit or more on hot days. As Arizona State University researchers documented in the desert city of Phoenix, the presence of trees makes the biggest difference for residents’ health during heat waves.

Nature has been honing this climate solution for hundreds of millions of years. Instead of turning to tech start-ups that come with a host of problems, let’s follow nature’s lead.

All the cool planets are doing it. Or at least the ones that want to be cool.

Notes and Resources

Life in the Hothouse: How a Living Planet Survives Climate Change, by Melanie Lenart. (University of Arizona Press, 2010).

The Emerald Planet: How Plants Changed Earth’s History, by David Beerling (University of Oxford Press, 2007). Also Making Eden: How Plants Transformed a Barren Planet, by David Beerling (University of Oxford Press, 2019).

The enduring world forest carbon sink by Yude Pan, Richard A. Birdsey, Oliver L. Phillips, Richard A. Houghton and colleagues, Nature 2024.

Middle Cretaceous wood from the Nanushuk Group, central North Slope, Alaska, by Judith T Parrish and Robert A. Spicer, 1988, in Paleontology. Also: Paleoclimatic significance of mid-Cretaceous floras from the Middle Clarence Valley, New Zealand, by Judith T. Parrish, Ian L. Daniel, Elizabeth M. Kennedy, and Robert A. Spicer, 1998 in Palaios.

Fire as Medicine: Salish Kootenai College’s new graduate program in natural resources emphasizes fire ecology, by Melanie Lenart, Native Science Report, May 13, 2022.

Collaborative stewardship to prevent wildfires, by Melanie Lenart, Environment 48(7): 8-21, 2006.

In a U.S. First, a Commercial Plant Starts Pulling Carbon From the Air, by Brad Plumer, New York Times, November 9, 2023.

Carbon Capture Startup Heirloom Raises $53 Million Backed by Bill Gates’ Breakthrough Energy, Microsoft, by Mark Segal, March 18, 2022, ESG Today.

Heirloom Carbon Technologies Announces $475 Million Investment to Establish North America’s Second Direct Air Capture Facility in Louisiana, Louisiana Economic Development News Release, June 24, 2024.

Neighborhood microclimates and vulnerability to heat stress, by Sharon Harlan, Anthony J. Brazel, Lela Prashad, William L. Stefanov, and Larissa Larsen, 2006, in Social Science and Medicine.