Global temperatures are running far above last year’s record-setting level, all but guaranteeing that 2015 will be the hottest year in the historical record — and undermining political claims that global warming had somehow stopped.

The National Oceanic and Atmospheric Administration, the American agency that tracks worldwide temperatures, announced Wednesday that last month had been the hottest September on record, and in fact took the biggest leap above the previous September that any month has displayed since 1880, when tracking began at a global scale. The agency also announced that the January-to-September period had been the hottest such span on the books.

The extreme heat and related climate disturbances mean that delegates to a global climate conference scheduled for Paris in early December will almost certainly be convening as weather-related disasters are unfolding around the world, putting them under greater political pressure to reach an ambitious deal to limit future emissions and slow the temperature increase.