I am surprised by this. As I recall, following 911, when all aircraft were grounded for several days there was a temperature spike because of the lack of contrails - suggesting a net cooling effect?
1. Is the deviation purely horizontal, or can the plane avoid making contrails by changing altitude? Avoiding contrails in 3D may be a lot easier than avoiding them in 2D. However, the modelling and forecasting would be more complex.
2. In crowded areas such as over Europe, planes follow strict routes from way point to way point. There is no scope to deviate from the route. That keeps air traffic control relatively simple, and safe, and allows it to be split across national boundaries. The planes avoid other planes in the 3D space. To allow regular route deviation would require much more sophisticated ATC systems and specifically algorithms.
There have been proposals for making ATC dynamic and forward looking, so each plane is given a unique flight path and this is checked to avoid all other flight paths. In effect, the planes avoid each other in both 3D space and in Time. So the plane from London to Milan may be in the exact same space as the plane from Barcelona to Berlin, but 60 seconds later.
I think in crowded airspace, contrail avoidance would need more advanced ATC; but equally, contrail avoidance would be built into the ATC system.
Contrails look superficially similar to the geoengineering technique of "stratospheric aerosol injection". There are quite a few differences in practice, but I would love to know which differences lead to the latter having a cooling effect while the former has a warming effect.
Thanks for bringing attention to this topic. I was also completely unaware of the effect of contrails on global warming and assumed that almost all of aviation's impact comes from the CO2 emitted through burning jet fuel. To discover that up to half the climate effects of aviation is down to non-CO2-effects changes the equation a lot. The way you describe it, it really is hard to understand why this has not been done and adopted for a long time, since it seems to be a very simple solution in order to reap an outsized benefit.
> We can do a very basic back-of-the-envelope calculation to sense-check this. The total fuel cost of flying from Barcelona to Berlin is probably around $2,000. If the flight burned 1% extra fuel due to rerouting, the extra cost for the flight would be around $20. Add the operational costs of the forecasting, and this could be $30 to $40. Then spread across all flights, not just the rerouted ones, and this falls back down to the $5 to $10 range again.
This would almost halve the emissions, removing contrail effects and only increasing CO2 effects by a tiny amount (1%), so it's worth it -- as long as the predictive modeling is good enough.
I am surprised by this. As I recall, following 911, when all aircraft were grounded for several days there was a temperature spike because of the lack of contrails - suggesting a net cooling effect?
Very interesting, two thoughts come to mind:
1. Is the deviation purely horizontal, or can the plane avoid making contrails by changing altitude? Avoiding contrails in 3D may be a lot easier than avoiding them in 2D. However, the modelling and forecasting would be more complex.
2. In crowded areas such as over Europe, planes follow strict routes from way point to way point. There is no scope to deviate from the route. That keeps air traffic control relatively simple, and safe, and allows it to be split across national boundaries. The planes avoid other planes in the 3D space. To allow regular route deviation would require much more sophisticated ATC systems and specifically algorithms.
There have been proposals for making ATC dynamic and forward looking, so each plane is given a unique flight path and this is checked to avoid all other flight paths. In effect, the planes avoid each other in both 3D space and in Time. So the plane from London to Milan may be in the exact same space as the plane from Barcelona to Berlin, but 60 seconds later.
I think in crowded airspace, contrail avoidance would need more advanced ATC; but equally, contrail avoidance would be built into the ATC system.
Contrails look superficially similar to the geoengineering technique of "stratospheric aerosol injection". There are quite a few differences in practice, but I would love to know which differences lead to the latter having a cooling effect while the former has a warming effect.
I’m curious why only 3% of flights cause 80% of warming. Is it to do with location, or the type of plane perhaps?
Thanks for bringing attention to this topic. I was also completely unaware of the effect of contrails on global warming and assumed that almost all of aviation's impact comes from the CO2 emitted through burning jet fuel. To discover that up to half the climate effects of aviation is down to non-CO2-effects changes the equation a lot. The way you describe it, it really is hard to understand why this has not been done and adopted for a long time, since it seems to be a very simple solution in order to reap an outsized benefit.
Wouldn't the extra fuel use of avoiding contrails offset the benefits? Is it enough short term benefit to justify the possible long term negatives?
It would be worth it. Quoting from this article:
> We can do a very basic back-of-the-envelope calculation to sense-check this. The total fuel cost of flying from Barcelona to Berlin is probably around $2,000. If the flight burned 1% extra fuel due to rerouting, the extra cost for the flight would be around $20. Add the operational costs of the forecasting, and this could be $30 to $40. Then spread across all flights, not just the rerouted ones, and this falls back down to the $5 to $10 range again.
This would almost halve the emissions, removing contrail effects and only increasing CO2 effects by a tiny amount (1%), so it's worth it -- as long as the predictive modeling is good enough.