TAMPA, Fla. (WFLA) — According to the Tampa National Weather Service, it was the hottest July on record in the Tampa Bay area, including the cities of Tampa, Plant City, Lakeland, Sarasota and Brooksville, with average temperatures of 2.5 to 4 degrees Fahrenheit above normal.
On Wednesday, a new study by Climate Central, a Princeton-based non-profit, found it’s not a coincidence, it’s climate change.
Across Florida, most cities experienced one of, if not their hottest Julys on record. Expanding further out that same fact is true for much of the US South, a big chunk of the Northern Hemisphere and the globe as a whole.
The heat this summer has been brutal. Miami had a streak of 46 days with a heat index of 100 or more. Phoenix, Arizona had 31 consecutive days at 110 or greater and beat their record for the hottest month by nearly 4 degrees Fahrenheit in July.
Meanwhile, in Europe, Rome shattered their all-time heat record by climbing above 107 and the Italian Island of Sardinia hit 118.
This widespread heat repeated in multiple parts of the world. In fact, the world beat its record hottest month of July by a whopping 1/2 a degree Fahrenheit as seen in the image below. It may not sound like much, but it’s an incredible margin when taking into account the whole planet and a huge leap from the former record.
Using Climate Central’s Climate Shift Index (CSI), the organization conducted an attribution report which found that 81% of the globe – 6.5 billion people – experienced a significant shift (A CSI of 3 or greater) in their temperatures on at least one day in July due to climate change. A CSI of 3 means that climate change shifted the local climate such that the heat was made three times more likely.
Perhaps more impressive was the scope and longevity of the heat. The study found that 2 billion people felt the very strong influence of climate change (CSI 3+) for each of the 31 days of July.
While human-caused climate change due to the burning of fossil fuels and emissions of heat-trapping greenhouse gases is the main reason for the global heat, a developing El Niño in the Tropical Pacific is also to blame, adding more heat to the mix.
Florida was particularly hard hit, with an average July Climate Shift Index of 4 in Tampa, 4.5 in Sarasota and 4.1 in Miami, meaning that climate change made the unusual heat 4 to 5 times more likely. The Climate Shift Index (CSI) maxes out at 5. Tampa reached that maximum shift of five on 20 separate July days, while Sarasota reached 26 days.
Although climate change is the primary reason for the Bay Area’s hot July, it is not the sole reason. Adding to the heat was lower than normal rainfall and thus more sunshine, as well as a persistent west wind off the Gulf bringing warmer morning temperatures to the area.
Still the Gulf of Mexico is record warm, and due to human-caused climate change has warmed 2 degrees F over the past few decades. Thus, when there is a west wind off the climate-heated Gulf, temperatures stay warmer.
The Climate Shift Index (CSI) is based on a peer-reviewed method. Here’s how it works.
The team at Climate Central estimates how often the temperature at a particular location is likely to occur in the current climate using both historical observations and 24 climate models. Then they also estimate that same likelihood in a climate without human-caused climate change. With that knowledge, they are able to calculate the “shift.”
The report says, “The rising frequency and intensity of extreme and record-breaking temperatures is consistent with the well-established scientific consensus on the effects of unprecedented levels of greenhouse gas emissions on the occurrence of extreme heat.”
The report goes on to say, “As the climate continues to warm, these impacts will almost certainly intensify. In the long-term, global and local temperature records are certain to be broken again and again in future years until greenhouse gas emissions are cut to zero.”