Currently in Portland — July 26, 2023: More sunshine and warmer

The weather, currently.

Wednesday’s high temp will top out at only a degree or two higher than Tuesday, but the lack of clouds will make the day feel a bit warmer and more summery. I’m sticking to my schedule of getting into the garden early, before it gets too hot. The herb spiral has its first plants, and later this week I’m going to try my luck with some seeds again. Hopefully the mellower temps give them a better chance to germinate… and hopefully winter doesn’t come on too quickly and kill them off before they bloom. And sure, winter is a ways off—but when you’re thinking in terms of growing seasons, it’s not that far away. (And honestly, I’m about a week away from giving in and putting up a few Halloween decorations.)

— Stella Harris

What you can do, currently.

The climate emergency doesn’t take the summer off. In fact — as we’ve been reporting — we’re heading into an El Niño that could challenge historical records and is already supercharging weather and climate impacts around the world.

When people understand the weather they are experiencing is caused by climate change it creates a more compelling call to action to do something about it.

If these emails mean something important to you — and more importantly, if the idea of being part of a community that’s building a weather service for the climate emergency means something important to you — please chip in just $5 a month to continue making this service possible.

Thank you!!

What you need to know, currently.

A new study, out Tuesday in the prestigious journal Nature Communications, has found that a key ocean current in the Atlantic is now expected to collapse by 2050, and as early as 2025.

The Atlantic Meridional Overturning Circulation (AMOC), the collapse of which was famously exaggerated in the movie The Day After Tomorrow, has collapsed many times in the past, most recently 12,000 years ago towards the end of the last ice age. Scientists think excessive meltwater coming from Greenland could be already pushing it toward another collapse, with the current now at its weakest in 1,600 years.

The most recent IPCC assessment concluded that a AMOC collapse is unlikely this century, and that global warming in excess of 8°C may be needed. A study published just seven years ago suggested just a 44% of a collapse by the year 2300, assuming Paris emissions reductions targets are met.

The new study uses a new method to estimate the effect of current and future emissions on the strength of the current and estimates a collapse by 2050, with a 95% confidence interval of 2025–2095. According to one of the researchers who helped collect some of the study’s data back in 2005, “it is mind boggling that almost 20 years later we are seriously looking at a collapse scenario in our lifetimes.”

German oceanographer Stefan Rahmstorf, whose past work has included study of the AMOC, has an extremely helpful 10 point overview of the study and how it has changed is view of what’s possible, including the possible likelihood of a near-term collapse.

The effects of a near-term collapse of the AMOC cannot be understated. The northward current provides warmth to the Gulf Stream that, if halted significantly, would sharply cool Northern Europe and worsen its shift towards drought while most of the rest of the world continues to warm. With the ocean no longer able to as effectively transfer heat between the Caribbean and Europe, Atlantic storms could greatly intensify in frequency and severity — according to research conducted by super scientist James Hansen.

Such consequences would be so dire that, according to the researchers, they should be “avoided at all costs”. In my person opinion — if there was ever a study that justifies world leaders declaring a climate emergency and winding down fossil fuels, it’s this one.

—Eric Holthaus