Niemeier and Tilmes on global cooling

23 July 2017 - geoengineering

NeiMeier Tilmes2017.PNGIn a recent Science perspective Niemeier (Max Planck Institute for Meteorology) and Tilmes ( National Center for Atmospheric Research) nicely sum up the present state of climate engineering with sulfur (DOI). In a nutshell: somehow inject a lot of sulfur into the atmosphere and make it counter global warming. The cooling effect of sulfur is well-known and can be observed with vulcanic eruptions. The planet has a definite surplus of sulfur, a long time ago the acid rain threat was removed when industries started to remove sulfur from their exhaust pipes.
The current Wikipedia page on stratospheric aerosol modification (SAM) is unusually optimistic about its prospects, the line "It presently appears that this proposed method could counter most climatic changes" has been around for a while and did not even spark an edit-war. But is this optimism justified?
Let the numbers do the talking: Niemeier and Tilmes present the following figures , yes climate engineering can solve global warming and extreme weather but it will require sulfur injections lasting over 160 year with one degree of cooling costing 20 billion dollar per year and 6700 jumbo jet flights per day, the equivalent of one Mount_Pinatubo per year. They also point out there are a lot of unknowns and not all the negative effects of climate change are mitigated. So it is not all good news and more needs to be done. A quick look then at the text of the Paris agreement: what, climate engineering not mentioned?

Herbicides and where to find them

22 July 2017 - Weeds

Corral2017.PNGAn interesting notion from Corral et al. in the Angewandte: when scouting for new herbicides look at existing antimalarial drugs (DOI). The rationale: malaria and plants share part of their evolution. Where the malaria parasite Plasmodium falciparum has an apicoplast (a kind of organelle used for storage of chemical compounds in a cell), plants and also algea have similar chloroplasts. In fact, organisms such as the malaria parasite possibly have at some point in their evolution gobbled up a red algea and simply kept.

The Corral team (a collaboration between the University of Western Australia and BASF) pitched a collection of known antimalarial 'drug-like' compounds against a well-known weed thaliana on agar resulting in eleven hits. Five of them were promoted to the soil testing competition and the winner was used as a scaffold for selection of another 39 commercially available analogues. Puzzlingly none of these 39 were able to beat the parent: a simple structure featuring a furanyl, an amide , a piperadine, a sulfinyl and a chlorophenyl group. In terms of mechanism another riddle to solve: the mode of action is inhibition of photosynthesis but the scaffold is not a known photosystem inhibitor. The reverse approach, discovery of new antimalarial targets based on known herbicides was not discussed.

Rik