We can't falsify claims about the future until we get there. If those in power justify bad policy on the basis of questionable "pathways", we can't beat them by claiming to know better about the future. But we do know that the pathways are highly uncertain. And we know that dirigisme is a bad approach to policy where there is a great deal of uncertainty and complexity. We don't need a better crystal ball to counter the bad policy. We just need to show that the uncertainty is such that we should rely on emergent order and discovery, rather than human-imposed order and central planning. Net Zero is an extreme case of bad policy based on uncertain expectations; some of them so uncertain that they haven't even been invented yet. We should not be planning a path to a particular outcome (Net Zero 2050). We should be internalising the externality (i.e. polluter pays) so that the climate impact is factored into our choices, and seeing what emerges as a result.

The Renewables Obligation, Renewable Heat Incentive and Feed-in-Tariffs renewable subsidy mechanisms generated nearly 150 different implicit carbon prices, from 1 to 300 p/kgCO2e (see linked chart). And there were plenty of other implicit carbon prices generated by other mechanisms. There should be only one.

The West is often asked to take on a greater share of the burden of decarbonisation, because of the climate debt it owes for centuries of carbon emissions. But do the sins of the father deserve to be visited on the children in this case?

A carbon price internalises the externality and allows the market to take account of the social cost of participants' choices. If there are other externalities, they should be internalised by their own mechanisms. If government has erected inappropriate barriers (e.g. regulations), then the inappropriate aspects should be redressed. Governments should not intervene to address barriers that are neither externalities nor unnecessary barriers of its own creation, but rather simple commercial obstacles. Sadly, governments intervene so much to help the winners they have picked that it is nonsensical to combine such a skewed environment with a mechanism like carbon pricing whose raison d'etre is to avoid the skewing. Yet economists (even ones as senior as Nobel Laureate Joseph Stiglitz and Professor Nick Stern, the Lord Stern of Brentford) are happy to oblige governments' rent-rewarding habits by pretending that the carbon price can and should be calculated taking into account the winner-picking interventions. The result is a nonsense carbon price that misleads policymakers and market players.

Labour's energy and climate-change proposals in their 2019 manifesto are vastly more expensive than they recognise - probably £1bn by 2030 and £1.5-2bn ASAP in the 2030s. This spending would reduce carbon emissions by less than 50% by 2030. One unintended consequence is that, despite so much infrastructure spending, electricity supply would occasionally be insufficient to meet the radically increased demand.

All parties are promising to reduce energy demand in buildings. The standard improvements are surprisingly limited (cavity wall insulation saves 7%, loft insulation saves 4%) and 2/3 of the properties are done already. Major improvement requires rebuilding. But at our current rate of demolition/conversion, it takes 22 years to replace 1% of the housing stock.

How credible are the parties' plans for mass tree-planting in the UK? The numbers sound big, but what does "big" really look like in forestry terms? What are the costs and impacts?

With UK parties competing to promise the earth, XR pushing eco-socialism, and hugely uneven national decarbonisation efforts, it's time to resurrect C4CS.