A German teenager dubbed the “anti-Greta” – climate sceptics’ answer to the schoolgirl activist Greta Thunberg – is set to address the biggest annual gathering of US grassroots conservatives. Naomi Seibt, 19, who styles herself as a “climate sceptic” or “climate realist”, will this week address the Conservative Political Action Conference (CPAC) near Washington, joining speakers including Donald Trump and Vice-President Mike Pence. Seibt is in the pay of the Heartland Institute, a thinktank closely allied with the White House that denies established science showing humans are heating the planet with dangerous consequences. CPAC will be the biggest stage yet...