Polish border guards boarded Greenpeace’s Rainbow Warrior vessel Monday and arrested the captain and one of the activists for impeding a coal ship from unloading at the Gdansk port.

On its website, Greenpeace said that its activists had sought to prevent a shipment of coal imported from Mozambique from being unloaded in Poland as part of a “climate emergency protest.”

Earlier, activists had vandalized the coal vessel with graffiti, painting “Poland Beyond Coal 2030” on the side of the ship’s hull.

Greenpeace Poland Program Director Paweł Szypulski justified the group’s actions by saying they were responding to an emergency.

“This is a climate emergency and we need to take action now,” Szypulski said. “This is our moment of truth and there is no turning back. We are taking action along with the millions of other people around the world demanding an end to fossil fuels. We have no time to waste.”

In a strange coincidence, at least one European nation has recently had to turn to Poland with its substantial coal reserves for back-up energy in time of need.

In late 2016, Germany found itself in dire need of energy after embarking on an ambitious green energy program and was obliged to turn to Poland for assistance.

Having wagered on renewables such as wind and solar energy as part of its ill-fated Energie­wende, the country’s program for energy transition, Germany found itself in an embarrassing situation when the wind failed to blow for several days and a thick fog descended upon many parts of the country.

As the output from renewables fell to just 4 percent of total demand, Germany had to turn to Poland, with its black coal-fired electricity plants, in order to meet its energy needs and emerge from its self-induced energy crisis.

Poland’s impressive track record notwithstanding, Greenpeace has doggedly tried to rein in the recalcitrant central European nation.

“Poland must abandon burning coal by 2030,” Mr. Szypulski proclaimed Monday, in reference to the target date for the phasing out of coal use in the European Union (EU).

Poland’s ruling Law and Justice (PiS) government has resisted the EU’s strong-arm tactics, saying it will embark on a gradual reduction in dependence on coal for electricity production, from around 80 percent today to 60 percent in 2030.

Along with Hungary, Poland has also rejected a call by the European Union for zero net greenhouse gas emissions by 2050, citing its negative effect on the economy.

Greenpeace has reiterated its total commitment to phasing out fossil fuels, regardless of its effect on the economy or the well-being of citizens.

“To keep global warming to 1.5°C and prevent a climate catastrophe, Greenpeace is calling on the EU to achieve total decarbonisation by 2040 and to cut greenhouse gas emissions by 65% by 2030,” the group said on its website.

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