What is it about climate change that turns august institutions into the intellectual equals of quivering jellyfish?

Last week, Germany's highest court upheld a constitutional complaint against the Federal Government on climate change. This decision, from the supreme court of a major country, could have consequences here in New Zealand.

The case, brought by nine climate change activists including minors from Nepal and Bangladesh, concerned Germany's emissions over the next 30 years.

Under pressure from protests, in 2019 the German federal Government legislated emissions targets for 2030 and 2050.

In effect, these targets are an emissions budget, the total number of tonnes of greenhouse gases Germany can emit between now and 2050.

At stake in the case was who gets to "spend" that emissions budget.

The Government has set emissions caps for each sector of the economy, but only up to 2030. With no plan beyond 2030, the activists complained this generation could consume too much of the CO2 budget, leaving too little for future generations.

The court upheld the activists' complaint. It directed the Government to set emissions budgets for the 2030s by the end of next year.

The court's logic is startling. Reducing emissions is all about violating individuals' rights. The court saw the case as being about whose rights should be violated.

In its decision, the court said:

"At some point in the future, even serious losses of freedom may be deemed proportionate and justified under constitutional law in order to prevent climate change…

"[Allowing] CO2 emissions in the present time constitute an irreversible legal threat to future freedom because every amount of CO2 that is allowed today narrows the remaining options for reducing emissions."

The court's decision was welcomed by most of the media and all but one political party in Germany. An environmental journalist at the daily newspaper Taz said the court's decision sounds "like Extinction Rebellion". It was probably meant as high praise.

Some responses were less positive.

The environment spokeswoman for the ruling Christian Democratic Union party said the decision was "to be accepted," before she stated the obvious. "[It is] almost impossible for today's legislators to decide on sector-specific emission reductions and climate protection measures 10 years in advance." Indeed.

A judge, writing anonymously, said the constitution sits above issues, policies, and governments. However, by putting climate ahead of constitutionally guaranteed rights, Germany's Federal Constitutional Court has abandoned the constitution, the judge said.

As if to underline the political nature of its decision, the court took the unusual step of publishing its decision in English and French, presumably because it hopes other countries will follow. It is not the first time Germany's courts have allowed the zeitgeist to influence their judgments.

The decision is significant for recognising the rights of future generations in constitutional law. On its face, that might be seen as positive, even obvious.

But there are two problems with the court's reasoning. First, it did not acknowledge the idea that only effective emissions policies can protect the rights of future generations. It did not consider whether a plan written by politicians in the early 2020s is the best way to cut emissions in the 2030s. (It is not.)

The second and far more disturbing problem is the court's presumption that reducing greenhouse gases requires fundamental rights to be violated.

"Any exercise of freedom involving CO2 emissions would have to be essentially prohibited at some point anyway in order to halt climate change," said the court.

This statement is untrue. International offsets, emissions removals via trees and other carbon capture technologies, emissions pricing, and low-emissions technologies like nuclear energy all reduce emissions effectively and without breaching individual freedoms.

The court did not consider these options.

There is every chance this decision from Germany's highest court will influence events here in New Zealand.

Like Germany, we use emissions budgets. They were introduced in the Zero Carbon bill in 2019. Thus, the German court's decision and its logic fit neatly with our set-up.

And there is sympathy for the court's thinking at the highest levels of government here.

So how does a country get to a point where its courts must choose whose rights to violate in order to lower emissions? The answer is simple. By removing every other more effective way to lower emissions.

Since coming to power in 2017, the New Zealand Government's constant refrain on climate has been economic transformation. More electric vehicles and renewables, less coal and gas, and so on.

But transformation is an expensive way to cut emissions, more costly and less effective than international offsets, emissions pricing, forestry, and other technologies.

But the Government wants transformation, and it knows that it cannot happen so long as other more affordable options are available.

So, the Government is removing those options. In 2019, it all but banned access to international offsets. The Climate Change Commission will likely recommend demotions for the ETS and forestry in its final report this month, clearing the way for transformation.

In practice, transformation will be delivered by massive subsidies for favoured technologies – EVs, solar and wind generation, and public transport – with hard bans for coal and gas in most sectors. Imports of all petrol and diesel light vehicles could end in 10 years.

This programme will not reduce emissions any more than current policies. But it will be ruinously expensive.

Which is how a country ends up in a position of deciding whose rights to violate to cut emissions. It requires ruling out every effective pathway to lower emissions to leave coercion as the only option.

And as politicians, officials and the courts choose whose rights to sacrifice next, they will say they are only trying to be fair, never questioning why anybody's rights had to be violated to cut emissions in the first place. These violations they will take as given.

Just as Germany's supreme court did last week.