This is Hidden Brain, I'm Shankar Vedanta.

The peak of summer usually means time spent outdoors, the mountains, the beach.

And for those of us who spent most of the past 15 months within the confines of our homes,

getting out feels more urgent than ever.

But as wildfire smoke cloaks the American West, blizzards lash Australia,

and deadly droughts strikes South Africa and Madagascar,

you might feel like turning right around and going back inside.

Scientists have been warning us for years about the looming threat of a warming planet.

And yet it's really hard for many of us to wrap our minds around this existential threat.

Why is that?

This week on Hidden Brain, a favourite episode where we visit the glaciers of Alaska,

to find out why our brains struggle to grasp the imminent dangers of global climate change.

This is Hidden Brain, I'm Shankar Vedanta. Last year my family and I took a vacation to Alaska.

This was a much needed long planned break. The best part? I got to walk on the top of a glacier.

The pale blue ice was translucent, sharp ridges opened up into crevices,

dozens of feet deep. Every geological feature, every hill, every valley, was sculpted in ice.

It was a sunny day and I spotted a small stream of melted water.

I got on the ground and drank some. I wondered how long this water had remained frozen.

The little stream is not the only ice that's melting in Alaska.

The Mendenhall glacier, one of the chief tourist attractions in Juneau,

has retreated over one and a half miles in the last half century.

Today you can only see a small sliver of the glacier's tongue from a lookout.

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