In the US, 92 all-time record high temperatures had been set through July 16, compared with only five all-time record low temperatures, according to data
from the US National Oceanic and Atmospheric Administration. Globally, 188 all-time heat records were broken versus 18 cool records.
Studies have showed that extreme heat will increase in frequency, intensity and duration because of the climate crisis. Gabriel Vecchi, a climate scientist at Princeton University, told CNN that the hot-and-cold record imbalance is a signal of the climate crisis
, and scientists have noted a trend in recent years that hot extremes are outpacing cold ones.
"This is what you would expect from a planetary warming that's been driven in large part from greenhouse gases; this is now the world we're living in," Vecchi told CNN, noting that "it's fair to think that almost every heatwave that we see right now has some influence from global warming."
All-time records were poised to topple in the UK on Monday and Tuesday, with temperatures running 10 to 15 degrees Celsius (as much as 25 degrees Fahrenheit) warmer than normal for this time of year.
The UK Met Office on Monday warned highs could approach 40 degrees Celsius (around 104 degrees Fahrenheit) for the first time -- a prediction that prompted meteorologists there last week to issue a "red" heat warning
for the first time ever. This forecast would break the record for the UK's hottest-ever temperature -- 38.7 degrees Celsius. The Met Office reported that Wales experienced its all-time hottest day on Monday and Scotland was at risk of seeing its own.
Further south, where the heat has been entrenched for more than a week, at least 1,000 people have died from heat-related illness in Portugal and Spain so far. Temperatures in Spain climbed to more than 45 degrees Celsius (114 degrees Fahrenheit) during its nearly week-long heat wave.
And in the US, more than 40 million people were under heat warnings and advisories on Monday from North Dakota to Texas, where high temperatures were expected to climb into the 90s and 100s. Dozens of temperature records could be broken through the week, forecasters warned.
Global scientists last year concluded that with every fraction of a degree of warming
, the effects of the climate crisis
worsen. While extreme heat events would still occur without climate change, the increasing intensity and frequency of these events in recent decades has been linked to the rise of fossil fuel emissions and observed global warming.
Imagine a bell-shaped curve of temperatures, Vecchi said, with cold on the left and warm on the right. As climate change shifts this temperature curve to the warmer side, the long tails of the curve increase by a proportionately larger amount than the middle, signifying the increasing likelihood of hotter events to happen and making cold events less likely.
Vecchi said the European heat wave is noteworthy, given its back-to-back nature, which will only continue as the planet warms and is all the more reason to prepare for a hotter future.
While this year isn't yet trending to be the hottest on record, despite the South Asian heat wave back in May and yet another heat dome in Europe, this year remains warmer than historical eras, which Vecchi said "is driven in large part due to the increase in greenhouse gases coming from fossil fuel burning."
"It's been a year of warmth," he said. "And these are the signatures of global warming."