Taking advice from Greta Thunberg

Suppose we were looking to build a bridge, say across Avon Gorge, to give us substantially more traffic capacity than the existing Clifton Suspension Bridge has. (The Dear Reader may insert their favourite joke about needing much more capacity for traffic leaving Bristol than for entering it).

It wouldn't be surprising that a lot of people would have strong opinions on what kind of bridge we should build. Imagine, however, that a 16 year old high school student was championing a bridge structure that comprised a sequence of road segments chained together and suspended from helium balloons. Imagine that such a proposal was lauded by at least 30% of the people involved as bold, innovative, and a wonderful example of youthful thinking, despite the fact that a first year engineering student could shoot the proposal as full as holes as a particularly perforated Swiss cheese.

That, ladies and gentlemen, is where we find ourselves with young Greta Thunberg.

Young Greta is clearly sincere , and cares deeply about the environment. Unfortunately, "sincerity" is as useful a factor in planning a 21st century industrial strategy as it is in building a bridge. If a bridge builder tells me that she "sincerely" believes it will support the expected peak weight of traffic in peak adverse conditions, and be durable for a lifetime of 50+ years, I will smile and nod; if anyone I care about will be traversing the bridge, I will then ask pointed questions about stress calculations, FEMs analysis, safety engineering analysis, and all the inconvenient hard science that lets us calculate at least a ballpark probability of the bridge suddenly failing and casting a few hundred people into the abyss. Nearly anyone can be sincere. To be correct requires actual maths, materials knowledge, ability to program R / Matlab / other mathematical tool of choice and produce a verifiable assertion, given generally accepted axioms, that the bridge will meet specs.

Somehow, I don't see this level of mathematical / physical / engineering rigour coming from young Ms Thunberg. Or her singer/actor parents, for that matter.

The correct response to Greta Thunberg and her parasitic (in every sense of the word) hangers-on is as follows:

• Give us a practical - by which we mean can-be-implemented-with-existing-technologies - 20 year plan for reducing carbon emissions world-wide by X%.
• Cover the top 10 current CO2 polluters; either assume they continue on current trend, or argue why they will change.
• You cannot assume any existing technology improves by more than 4% per year for cost/efficiency.
• Include the expected economic impact on the top 10 world economies.

Greta would (quite rightly) say: "I'm 16 years old, how could you possibly expect me to answer this?"

Greta käraste, if you can't be expected to answer the hard questions, why should we listen to your easy answers?