Reflective plants and global warming – 1

Scientists come up with all sorts of original ideas to secure some funding and secure their jobs for the next few years! Check out this one from the BBC:

Farmers could help curb rising global temperatures by selecting crop varieties that reflect solar energy back into space, researchers say. …

Some crop varieties are naturally more reflective than others. A field of more reflective leaves will send more solar energy back into space than a field of a more absorbent variety.

Yes, you could feasibly reflect a little bit more heat back by doing this. But how much? Over 70% of the earths surface is ocean, which absorbs most of the light that hits it. Only around 30% of the land area is feasibly able to be farmed, and only a tiny fraction of that would be practical to actually plant in more reflective crops (encouraged by subsidies of course). Maybe you could plant 0.2% of the earth in reflective crops as a generous estimate?

“But another possibility for the future would be to produce a [leaf] surface that differs in reflectivity at different wavelengths, so it could selectively absorb wavelengths involved in photosynthesis.”

Newsflash: Leaves already do that. That is why they look green – they absorb the red light (which they use for photosynthesis), and reflect the green, which they don’t use. It is also why plants stay cool on a hot day while most surfaces get hot – they aren’t absorbing radiation they don’t need. But good on whoever thought up this idea, they’re bound to get someone to fund it, it sounds plausible.

So the plan is to plant a tiny fraction of the earth in plants that reflect a tiny fraction more light back into space (remembering plants are already extremely efficient at this so you can make only minor improvements). Supported by massive subsidies. And all while hoping that the market doesn’t act by planting more “bad” plants in unregulated countries to meet consumer demand.

Judge it for yourself.

Reflective plants and global warming – 2