Stories by Andrew Freedman

El Niño may make a comeback this fall and winter

Note: Temperature anomalies are relative to the 1985 to 2012 average; Data: National Oceanic and Atmospheric Administration; Map: Chris Canipe/Axios

Odds favor a return this year of the climate phenomenon known as El Niño — above-average sea surface temperatures in the equatorial tropical Pacific Ocean and related changes in weather patterns.

Why it matters: Depending on their intensity and exact location, El Niño events can alter global weather patterns — favoring above average precipitation in the parched state of California, for example, while inducing drought elsewhere. Typically, such events develop sometime in late summer or early fall, and peak during the winter.

In hot water: Global warming amplifies risk of marine heat waves

Snorkeler surveying bleached coral in the Maldives in 2016.
Snorkeler surveying bleached coral in the Maldives in 2016, during the third global coral bleaching event. Photo: XL Catlin Seaview Survey

Tens of millions across the northern hemisphere have experienced record heat waves this summer, further driving home how climate change is already tilting the odds in favor of more severe extreme heat events in the years ahead.

A similar dynamic is emerging in our oceans, and this could have far-reaching implications. A new study, published today in the journal Nature, finds that marine heat wave days have doubled between 1982 and 2016, which cannot be explained by natural variability alone. What's new and significant, though, is what the study projects for the future.

July 2018 was third-warmest such month on Earth, NASA finds

Global surface temperature anomalies during the month of July 2018.
Global average surface temperature anomalies during July 2018, in degrees Celsius. Credit: NASA GISS.

July 2018 was the planet's third-warmest such month since reliable measurements began in 1880, with a global average surface temperature of 1.4°F warmer than the 20th century average — this means the top 3 warmest Julys have occurred in 2016, 2017, and 2018, respectively.

Why this matters: July saw a spate of extreme heat events around the world, from all-time record heat and wildfires in Scandinavia, to the warmest month in California history. The July 2018 ranking, while preliminary, is significant since unlike in 2016, there was no El Niño present to add more heat to the climate system.