Never change a running system: what is a sustainable method, and how can it be assessed?
Never change a running system. Everybody knows this phrase, and isn't it true?
Every lab has established methods, and that's precisely why nobody questions them: everyone is confident they work, the experiments are reliable and reproducible, so why change anything? Changing methods is time-consuming, complex and costly, and altering one part of an experimental routine often means having to adjust other parts too. But the question worth asking separately is whether an established method is actually a sustainable one, and those two things, "it works" and "it's sustainable", are not automatically the same claim.
Green chemistry already answered part of this
In 1998, Paul Anastas and John C. Warner published the twelve principles of green chemistry, a framework that still guides how chemists design experiments that use less energy and fewer resources, produce less waste, and rely on safer, more environmentally benign substances. Those principles are a genuinely useful starting point for assessing any lab method, chemical or otherwise, against a sustainability standard rather than just a "does it work" standard.
What this looks like in practice
Fetal bovine serum, FBS, is a widely used cell culture supplement with well-documented ethical implications, and scientists working with cell cultures are increasingly expected to move toward FBS-free media where the science allows it. DNA extraction offers another concrete example: a protocol that only needs to lyse bacterial cells to release genomic DNA, immobilising it on a membrane for direct use in a PCR reaction, can be considerably more resource-light than a more involved column-based purification, without sacrificing the reliability of the result. Even something as simple as how samples are stored, at room temperature versus in a freezer, is worth revisiting method by method rather than assumed by default; a freezer isn't always essential.
How to actually assess a method
Ask whether the underlying materials or technology have moved on since the protocol was first written, since methods built around older consumables sometimes carry legacy steps that newer materials no longer require. Check whether a validated, lower-impact alternative already exists in the published literature, since substitution is far less risky when someone else has done the validation work already. And weigh the genuine cost of re-validating a method against the ongoing cost, in energy, reagents, plastic and animal-derived materials, of leaving it unchanged; that comparison often tips further toward changing than people assume before they've actually run the numbers.
The point isn't change for its own sake
Plenty of running systems really are the most sustainable option available, and changing them purely for the sake of it would be wasted effort. The goal is making sure that's a conclusion actually reached by checking the method against current standards, rather than an assumption nobody has revisited since the protocol was first written.
