The bill was put forward by Deputy Thomas Pringle, who sees this as a matter of "ethical financing." It's a message to energy companies that both deny human-made climate change and lobby politicians to look the other way, he says.

Ireland's decision won't have the greatest environmental impact given its relative size, but this is still an aggressive move when many other countries aren't ready or willing to drop their support for conventional energy. It's a particularly sharp contrast to the US, whose new leadership is already going to great lengths to suppress climate change science and protect the fossil fuel industry.