Monday may have set a global record for the hottest day ever. Tuesday broke it

The entire planet sweltered for the two unofficial hottest days in human record-keeping Monday and Tuesday, according to University of Maine scientists at the Climate Reanalyzer project.

For two straight days, the global average temperature spiked into uncharted territory. After scientists talked about Monday's dramatic heat, Tuesday soared 0.17 C even hotter, which is a huge temperature jump in terms of global averages and records.

The same University of Maine climate calculator — based on satellite data and computer simulations — forecasts a similar temperature for Wednesday that would be in record territory, with an Antarctica average that is a whopping 4.5  C warmer than the 1979-2000 average.

High temperature records were surpassed July 3 and 4 in Quebec and northwestern Canada and Peru. Cities across the U.S. from Medford, Oregon to Tampa have been hovering at all-time highs, said Zack Taylor, a meteorologist with the U.S. National Weather Service. Beijing reported nine straight days last week when the temperature exceeded 35 C.

"The increasing heating of our planet caused by fossil fuel use is not unexpected; it was predicted already in the 19th century after all," said climate scientist Stefan Rahmstorf at the Potsdam Institute for Climate Research in Germany. "But it is dangerous for us humans and for the ecosystems we depend on. We need to stop it fast."

The daily but preliminary and unofficial heat record comes after months of "truly unreal meteorology and climate stats for the year," such as off-the-chart record warmth in the North Atlantic, record low sea ice in Antarctica and a rapidly strengthening El Niño, said University of Oklahoma meteorology Prof. Jason Furtado.

This global record is not quite the type regularly used by gold-standard climate measurement entities like the National Oceanic and Atmospheric Association. But it is an indication that climate change is reaching into uncharted territory. It legitimately captures global-scale heating and NOAA will take these figures into consideration when it does its official record calculations, said Deke Arndt, director of the National Center for Environmental Information, a division of NOAA.

"In the climate assessment community, I don't think we'd assign the kind of gravitas to a single day observation as we would a month or a year," Arndt said. Scientists generally use much longer measurements — months, years, decades — to track the Earth's warming. In addition, this preliminary record for the hottest day is based on data that only goes back to 1979, the start of satellite record-keeping, whereas NOAA's data goes back to 1880.

But Arndt said that we wouldn't be seeing anywhere near record-warm days unless we were in "a warm piece of what will likely be a very warm era" driven by greenhouse gas emissions and the onset of a "robust" El Niño. An El Niño is a temporary natural warming of parts of the central Pacific Ocean that changes weather worldwide and generally makes the planet hotter.

Human-caused climate change is like an upward escalator for global temperatures, and El Niño is like jumping up while standing on that escalator, Arndt said.

On Tuesday, Earth's average temperature spiked at 17.18 C, according to the University of Maine's Climate Reanalyzer, a common tool often used by climate scientists for a good glimpse of the world's condition. Tuesday's temperature was nearly a full degree Celsius warmer than the 1979-2000 average, which is itself is warmer than the 20th and 19th century averages.

The reanalyzer is based on an NOAA computer simulation intended for forecasts that use satellite data. It is not based on reported observations from the ground. So this unofficial record is effectively using a weather tool that is designed for forecasts, not record-keeping.

The global daily average temperature for July 3 came in at 17.01 degrees Celsius. This average temperature may not seem that hot, but it's the first time in the 44 years of this dataset that the temperature surpassed the 17 C mark and then it went even higher.

"A record like this is another piece of evidence for the now massively supported proposition that global warming is pushing us into a hotter future," said Stanford University climate scientist Chris Field, who was not part of the calculations.