Have we reached peak alarmism on climate change?

The question occurs after the muted reaction last week to the latest forecast from the United Nation’s Intergovernmental Panel on Climate Change.

In case you hadn’t heard we’re all doomed, yet the world mostly yawned. This is less complacency than creeping scientific and political realism.

The U.N. panel says the apocalypse is nigh—literally. According to its calculations, global carbon emissions must fall 45% by 2030—twice as much as its earlier forecasts—and the world must wean itself entirely off fossil fuels over three decades to prevent a climate catastrophe that will include underwater coastlines and widespread drought and disease.

These reductions are “possible within the laws of chemistry and physics,” said the report’s co-author Jim Skea, and that’s a relief. But he added: “Doing so would require unprecedented changes,” and the report said some methods “are at different stages of development and some are more conceptual than others, as they have not been tested at scale.”

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Also not tested over time are the panel’s climate models, which are sensitive to forecasts of population growth, ocean currents and radiative forcing, among myriad scientific variables that are not well understood. The IPCC’s forecasts keep changing because climate models are still in an early stage of development.

Amid the Paris climate conclave of 2015 the IPCC predicted that two degrees of warming over pre-industrial levels would prevent Armageddon. Now after further study the IPCC has lowered its safety line to 1.5 degrees.

According to the IPCC, two degrees of warming would destroy all coral reefs while a 1.5 degree temperature increase would wipe out around 90%. About 80 million people could be affected by rising sea levels if temperatures rise by two degrees versus 70 million with 1.5 degrees of warming. Some 350 million city dwellers could experience a water shortage if temperatures increase by 1.5 degrees and 411 million if they rise by two.

In other words, humanity is doomed under the IPCC’s models no matter what we do. Nonetheless, the IPCC is urging immediate, drastic and large-scale economic changes that would affect everything from the kinds of cars people drive to foods they eat. Millions of acres of farmland would have to be converted into forests or plastered over with solar panels.

Some $2.4 trillion in annual investment in climate mitigation and adaptation—about 2.5% of world GDP—would also be needed over the next two decades. Yet as economist Bjorn Lomborg noted in these pages last week, the IPCC estimated a few years ago that unmitigated global warming in 60 years would cost between 0.2% and 2% annually of world GDP. So we’re supposed to spend more as a share of GDP now than the problem will cost in 60 years when the world would have far more resources to cope with it?

Perhaps the sheer implausibility of these remedies helps to explain why the reaction to the U.N. report was so muted. Why turn the entire global economic system upside down if we’re all doomed anyway?

The IPCC also recommends a carbon tax to spur more investment in renewables and embryonic and expensive technologies to capture carbon from the atmosphere. On cue, Exxon Mobil last week pledged $1 million as political penance to promote a carbon tax, which the company knows would be passed onto consumers.

A carbon tax is in theory the best way to combat the climate externalities of fossil fuels. And we might support a carbon levy if it were offset by the elimination of other taxes—such as the income tax. But the left wants a carbon tax in addition to all current taxes to control more of the private economy.

This explains the frequent political backlash to carbon taxes where they’ve been tried. After Australia’s Labor Party implemented a $23 per ton carbon tax in 2012, conservatives rode to power on a campaign of repeal as electricity and gasoline prices soared. Canadian provincial governments including Alberta’s New Democratic Party Premier Rachel Notley are protesting Justin Trudeau’s carbon tax proposal.

Not that these carbon taxes would make an iota of a difference according to the IPCC’s models. Most carbon taxes are around $20 per ton. Yet the panel estimates a global carbon price of between $135 to $5,500 per ton—which would increase the cost of gas by between $1.20 to $49 per gallon—would be required to keep warming below 1.5 degrees Celsius. Europe is also proving the limits of its carbon sacrifices, as renewables fail to meet expectations and even the green believers in Germany increase their use of coal.

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