As parts of India grapple with a persistent severe heatwave extending from last month into June, NASA scientists have disclosed that May 2024 was the hottest May on record. This marks an unprecedented milestone of 12 consecutive months with record-high average global temperatures, according to researchers from NASA’s Goddard Institute for Space Studies (GISS).

“It’s evident that we are confronting a climate crisis,” emphasized NASA Administrator Bill Nelson. “Communities across America — from Arizona to California to Nevada — and communities worldwide are experiencing firsthand unprecedented levels of extreme heat. NASA and the Biden-Harris Administration acknowledge the urgency of safeguarding our home planet. We are delivering crucial climate data to enhance lives, livelihoods, and benefit humanity as a whole.”

His streak of record temperatures coincides with a long-term warming trend primarily attributed to human-induced greenhouse gas emissions. This trend has become increasingly pronounced over the past four decades, with the last ten consecutive years ranking as the warmest since the late 19th century when record-keeping began.

Prior to this 12-month streak, the longest previous streak of record monthly temperatures lasted seven months, occurring between 2015 and 2016.

“We’re witnessing more hot days, more hot months, and more hot years,” noted Kate Calvin, NASA’s chief scientist and senior climate advisor. “We understand that these temperature increases are driven by our emissions of greenhouse gases, and they are impacting communities and ecosystems globally.”

In NASA’s analysis, a temperature baseline typically spans several decades, often 30 years. The average global temperature over the past 12 months was recorded at 2.34 degrees Fahrenheit (1.30 degrees Celsius) above the 20th-century baseline period from 1951 to 1980. This exceeds the 2.69 degrees Fahrenheit (1.5 degrees Celsius) level relative to the late 19th century average.

To gather this data, NASA scientists utilize information from tens of thousands of meteorological stations on land, as well as instruments on ships and buoys. The raw data undergoes rigorous analysis, which includes adjusting for factors such as the distribution of temperature stations and the urban heat island effect.

Natural phenomena such as El Niño and La Niña, which respectively warm and cool the tropical Pacific Ocean, play a significant role in year-to-year variations in global temperatures. The robust El Niño event that commenced in spring 2023 contributed to the extreme heat experienced during the summer and fall of that year.

As of May 2024, NOAA (National Oceanic and Atmospheric Administration) projected a 49% likelihood of La Niña developing between June and August, with the probability increasing to 69% between July and September. A La Niña event has the potential to mitigate average global temperatures for this year by cooling the tropical Pacific region.