Indirect greenhouse gases: why the 'root causes' approach isn't working

From the current New Scientist:

Of all the global warming that has happened since the pre-industrial era, about 15 per cent has been caused by emissions other than greenhouse gases, mainly carbon monoxide and VOCs [volatile organic chemicals]. ‘Forgotten’ pollutants cause warming, Alec Luhn, 'New Scientist', dated 20 June 2026

Some countries target emissions of these 'indirect greenhouse gases' indirectly, but most efforts aimed at reducing the rate of climate change are focused on carbon dioxide, methane and other gases that more directly affect the composition of the atmosphere. The same article tells us that black carbon (soot) is also excluded from these efforts and from national emissions data.  

The flaw in this approach - and it's a flaw that bedevils much environmental and social policy - is that in targeting a problem we try to identify its root causes and then aim to eliminate or attenuate them. But, as this example shows, when we are dealing with problems that have multiple causes and significant time lags, it's almost impossible to exhaustively identify these root causes. In this example, Mr Luhn points out that these indirect greenhouse gases plus black carbon are estimated to have contributed about  0.3°C of warming, which is quite significant. But there may be even more causes of climate change of which we are not aware....

Which is why I advocate targeting the outcomes that we wish to see, rather than the supposed means of achieving them. Our knowledge of environmental and social relationships though, is always growing, and it makes more sense (to me) to recognise that we can't identify all the root causes and, rather than assume that we do and legislate accordingly, we should be encouraging people to keep researching into those root causes or to acknowledge that there might be more efficient ways of solving our problems than trying to find them. In the climate change example, we should be very clear about what we want to see: most probably, we'd want to see a range of physical, biological, ecological, social and financial measures of climate impacts to fall within an approved range for a sustained period. Why then, shouldn't we reward people for achieving that goal, rather than the alleged means of achieving it? In this example, again, it might be more efficient to look at solutions other than, or complementary to, reducing greenhouse gas emissions. Such approaches are being followed, but there is no coherent way of rewarding the most promising of them; nothing along the lines of the efforts to control emissions of those gases that fossilised science once told us contribute most to climate change. 

A Social Policy Bond regime, applied to climate change, would take that long-term view, and once we have clarified exactly what outcomes we wish to see, reward those who take steps to achieve them. A bond regime would reward the most cost-effective approaches and terminate those that are least promising. The same paradigm applies to other social and environmental approaches, especially those that are so complex that current policies are failing. 

For more about what I think about root causes, see here and here. For more about Social Policy Bonds in general see here; as applied to climate change see here.