When Swedish eco-pessimist Greta Thunberg came to New York to shout, “How dare you!” last month, she maintained her climate purity by traveling on a carbon-neutral, solar-powered yacht.

Now that she’s in Canada, the teen doomsayer hasn’t explained how she’ll travel 4,000 miles home to Sweden without flying. She’s given up airplanes because she believes their greenhouse emissions drive cataclysmic climate change.

Air travel, which accounts for 2 percent of global emissions, has become the great bogeyman for climate alarmists, sparking a backlash against airlines.

Punitive eco-taxes, aviation regulations, activist investors, green NGOs and climate-aware passengers conspire to force airlines and manufacturers to lower CO2 emissions by using less fuel, which accounts for 99 percent of aviation’s carbon footprint.

No one has said it explicitly yet, but this relentless pressure to reduce emissions appears to have been a significant factor in the disastrous safety failures of the Boeing 737 MAX aircraft, which resulted in two fatal crashes in the past year, claiming 346 lives.

The warning from Boeing’s catastrophes is that climate ideology can have fatal consequences.

The 737 MAX was trumpeted as “Boeing’s game changer.” It reduced emissions by 14 percent and Boeing raced it into production to compete with a climate-friendly new offering from Airbus.

But in order to achieve its green goal, Boeing had to use much bigger engines that didn’t fit in the usual position under the wing of the repurposed, 53-year-old 737 design.

The engines had to be moved forward and hoisted higher.

As a result, the aerodynamics changed, and the planes had a tendency to pitch up and potentially stall on takeoff. Boeing’s solution to this hardware defect was an imperfect software bandage that would automatically correct the pitch. In both crashes, preliminary investigations found this software kicked in even when the plane wasn’t stalling, with lethal consequences.

To understand the 737 MAX fiasco, you must go back to 2011, when Boeing faced an existential challenge from Airbus’ low-emission A320neo, which had been developed under stringent new European aviation climate regulations.

American Airlines, an exclusive Boeing customer, was threatening to defect to the A320neo, as the New York Times reported. Three months later, Boeing announced the 737 MAX.

The eco-imperative for Boeing was more than woke posturing. Its customers, the airlines, were demanding better environmental performance because of regulations and mounting threats from climate-conscious institutional investors. Biofuels and electric planes aren’t yet viable, so fuel efficiency was the only option.

While aviation escaped inclusion in the 2015 Paris climate agreement, the following year, the UN’s International Civil Aviation Organization bound 191 member nations to reduce CO2 emissions by a colossal 50 percent by 2050 or spend 2 percent of revenues buying offsets.

In other words, airlines have to pay to plant trees to satisfy emission reduction targets. This buys them cover to expand the industry.

The decarbonization imperative for Boeing was clear. Carriers like United, which has vowed to become “the most environmentally conscious airline in the world,” rushed to buy the 737 MAX. So did American Airlines, whose CEO boasted, “We’re much more environmentally friendly than United Airlines right now because we’ve invested in more fuel-efficient aircraft.”

This was the priority driving Boeing. Its 2018 report “Build Something Cleaner” featured the 737 MAX on the cover and boasted that the plane will “emit 305,040 fewer tons of CO2 and save more than 215 million pounds of fuel per year, which translates into more than $112 million in cost savings.”

Declaring its commitment to halving carbon emissions by 2050, it said, “Reducing emissions is aligned to our customers’ strategic desire to decrease fuel use, a major cost and priority in their purchasing decisions. Our customers increasingly require that Boeing’s products and services include environmentally progressive attributes.”

Investors, too, increasingly demand improved “carbon performance.”

In March, a study funded by airline investors with $13 trillion of assets under management chastised the aviation industry for not doing enough to fight climate change.

“As investors, we need clarity about [whether] the sector is to make its contribution to the goals of the Paris Agreement” was a typical comment from investment bank BNP Paribas.

The pressure on Boeing to deliver climate outcomes was relentless. A flawed retrofit design was the price, when Boeing decided it couldn’t wait another decade to design a new aircraft.

Indonesia’s Lion Air was the 737 MAX’s first customer in 2012.

In 2018, one of Lion Air’s planes crashed, killing 189 people.

A year later, the 737 MAX fleet is still grounded.

Boeing has lost more than $25 billion in market value and this week belatedly replaced a senior executive, after messages came to light between senior pilots complaining about the 737 MAX software “running rampant” during a test simulation in 2016.

We need to know if safety considerations at Boeing took a back seat to producing a climate-friendly plane. There are implications for other companies.

After all, as Bernie Sanders says, “You cannot go too far on the issue of climate change. The future of the planet is at stake.”

If you believe the world is going to end in 11 years, the deaths of a few poor air travelers is a small price to pay for appeasing the climate gods.

Cycle of folly

Now the city wants to adjust traffic lights to suit cyclists and further slow cars and buses. It’s supposed to make cycling safer after a spate of deaths over the summer. But the inconvenience and economic damage will do nothing to address the real problem of lawless, entitled cyclists who run red lights, ride the wrong way down one-way streets and pose a lethal threat to pedestrians and themselves.

Only 3 percent of New Yorkers use bikes as their primary mode of transportation, compared with 28 percent who walk and 40 percent who use cars or buses.

It’s time to give the streets back to the majority and admit that Mayor Bill de Blasio’s bike revolution is a big fake flop.

It’s the ‘right’ way

Progressive poster boy Justin Trudeau won the Canadian election but lost the popular vote. Will he be forever damned as the “illegitimate” prime minister? Will his term be crippled by attempts to overthrow him? Will the conservative opposition demand an end to the Westminster system? Will the Canadian media spend the next four years advancing conspiracy theories about how he stole the election?

Hardly. Unlike sore-loser leftists, conservatives accept the umpire’s decision.