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Delays, waiting to land or resorting to longer flight paths because of busy air corridors are just three examples of increased jet fuel consumption.
"Climate change has not stopped and there is no vaccine against the climate crisis," said Monika Langthaler, director of the Austrian World Climate Summit.
The "catastrophic" decline in wildlife has been caused by deforestation, unsustainable agriculture and illegal wildlife trading.
'My gap year is over': Greta Thunberg heads back to school