NASA is clear. Last July was the hottest month globally…since 1880. “Our data confirms what literally billions of people across the planet felt: July 2023 temperatures made it the hottest month on record,” say scientists at the Goddard Institute for Space Studies (GISS), whose goal is to monitor long-term changes over decades and centuries.
The temperature in those 31 days was 0.24 degrees Celsius (0.43º Fahrenheit) warmer than any other July in the NASA database and was 1.18º C (2.1º F) warmer than the recorded average. between 1951 and 1980 -"normal" climate values are those defined for several decades, generally 30 years.
“In every corner, people are experiencing firsthand the effects of the climate crisis. The science is clear. We must act now to protect our communities and the planet; it's the only one we have," NASA Administrator Bill Nelson said in a statement.
Parts of South America, North Africa, North America and the Antarctic Peninsula were especially warm, experiencing temperature rises of around four degrees Celsius (7.2 Fahrenheit) above average. Extreme heat this summer put tens of millions of people under heat advisories and was linked to hundreds of heat-related illnesses and deaths.
This July record also continues a “long-term trend of human-caused warming, driven primarily by greenhouse gas emissions that has become apparent over the past four decades,” NASA says. The previous record was obtained in July 2019.
According to data from the US Space Agency, the five hottest joules recorded since 1880 occurred in the last five years. “The climate crisis is affecting people and ecosystems around the world, and we expect many of these impacts to increase with continued warming,” said Katherine Calvin, senior climate adviser at NASA Headquarters in Washington.
NASA derives its record from surface air temperature data from tens of thousands of metrological stations, as well as sea surface data acquired by instruments on ships and buoys. This raw data is analyzed using methods that even take into account urban warming effects, which could skew the calculations.
“Not only was this July warmer than any previous July, it was the warmest month in our record, going back to 1880,” says GISS director Gavin Schmidt. “The science is clear, this is not normal. The alarming warming across the planet is mainly due to human-caused greenhouse gas emissions. And that rise in average temperatures is fueling the dangerous extreme heat that people are experiencing around the world,” he adds.
The Space Agency notes that it was high sea surface temperatures that contributed to July's record heat. The ocean waters are much warmer and that causes more warm water to go into the atmosphere, which intensifies storms and creates hurricanes. In the eastern tropical Pacific there were particularly warm areas, evidence of El Niño, which began in May.
“Phenomena such as El Niño or La Niña, which warm or cool the Pacific Ocean, may contribute a small part of the interannual variability of global temperatures. But these contributions are not normally noticed when these climatic events begin to unfold in the northern hemisphere summer," the scientists explain.
NASA expects to see the biggest El Niño impacts in February, March and April 2024. In addition, Schmidt says, "there are other things going on beyond El Niño," with "extreme temperatures in the North Atlantic" and elsewhere and "a persistence of sea surface temperature anomalies".
The effects of this global warming translate into "heat waves and more intense rains" and contribute "to the growth of forest fires in areas that have been affected by high temperatures." Consequences that are being seen, for example, in the recent fires in Hawaii, the deadliest in the last century in the United States, with almost a hundred victims on the island of Maui.
"The storm tracks have been moving north with climate change. Hawaii has been getting less precipitation overall, decade after decade. We will see bigger and more intense wildfires," says the GISS director.
The increase in temperature in the ocean, say experts from the US Space Agency, is a general detriment to the planet's economy, "not only in terms of food, but also of trade, with maritime routes affected by having more storms."
Some economic effects that will also suffer the millions of people who live along the coast. "Storms and hurricanes will affect the coastal infrastructure and there will be more flooding," they say. The temperature of the sea can even contribute to "there being much stronger snow storms, although it seems counterintuitive."
