The Carbon Footprint of Everything: What You Don’t Know Can Hurt the Planet

Carbon footprints are more than just a buzzword; they are a scientific measure of our impact on the planet’s climate system. Mike Berners-Lee’s How Bad Are Bananas? meticulously breaks down this science to reveal the hidden complexities behind what we often oversimplify.

At its core, a carbon footprint accounts for all greenhouse gases, including methane and nitrous oxide, converted into carbon dioxide equivalent (CO2e) based on their warming potential. This means that not all emissions are equal; for example, methane traps heat more effectively than CO2, making its footprint larger per unit emitted.

The book explains how emissions at high altitudes, such as those from airplanes, have a multiplier effect of about 1.9 due to their enhanced warming impact. It also distinguishes between direct emissions—those from burning fuel or electricity—and indirect emissions embedded in the supply chain of products and services.

Interesting facts emerge, such as first-class train travel having roughly double the carbon footprint per passenger mile compared to standard class due to fewer seats and heavier weight per traveler. Similarly, cycling’s carbon footprint depends heavily on the carbon intensity of the food consumed to fuel the activity, linking diet with transport emissions.

Berners-Lee’s scientific approach demystifies carbon accounting and encourages readers to develop a carbon instinct—a natural sense of the carbon cost of everyday choices. This understanding is crucial for prioritizing effective actions and advocating for systemic change.

For those eager to delve deeper into the science of carbon footprints, the book and its reviews provide a rich resource. See detailed perspectives at