Canadian rock 'n' roll firebrand Neil Young has always made clear his stance on environmentalism.

On his latest and 39th album, Colorado, the rock and folk pioneer doubles down on his position, disgusted by his peers' recklessness, but heartened by the younger generation's fervour in championing the earth.

"You might say I'm a few bricks short of a load," he sings candidly in She Showed Me Love, a 13-minute jam punctuated by enthusiastic riffs from his trademark distorted guitars. "I saw old white guys trying to kill mother nature" he continues, later adding that he also "saw young folk fighting to save mother nature".

Like his best works, the 10 tracks in Colorado - the first time in seven years he is making music with his long-time band Crazy Horse - are raw and visceral.

They sound like they were recorded live, which emphasises the immediacy of his messages.

Yet, Young's unadorned singing is also backed by flawless, harmonised backing vocals.

The melodies found in the punk-ish Help Me Lose My Mind ("I got a face that gets me in trouble/I got a voice that does its damage") alleviate the gravity of his tunes.

Despite his misgivings about the earth ("We saw the people rise, divided/We fought each other while we lost our coveted prize," he warns in the melancholic Green Is Blue), the 73-year-old still has faith in humanity.

The people are strong, he declares in gospel-like singalong Rainbow Of Colors ("There's a rainbow of colours in the old USA/ No one's gonna whitewash those colours away").

Older than Young by just a couple of months, Northern Irish singing icon Van Morrison has also released his newest album in the same week.

He has been on a roll since 2015, putting out up to two albums a year. Three Chords And The Truth is his latest and 41st full-length release.

The 14 tracks, all original tunes, run the gamut of styles he has been known for since his music career took off with Brown Eyed Girl in 1967.

March Winds In February and You Don't Understand are old-school soul numbers driven by jazzy rhythms, while Bags Under My Eyes is an authentic country tune that looks back at his long and storied life in music ("I'm still out here on the go").

Days Gone By, an extended, seven-minute R&B number with an unrelenting bass groove, is a self-reflective ode to farewells ("Hopefully, we can make mistakes and then we grow") that also incorporates Scots folk tune Auld Lang Syne.

Morrison's voice is still strong and unwavering, whether it is in the slow waltz of If We Wait For Mountains or the mellow strains of the meditative Dark Night Of The Soul ("I'm on my way to understanding/Things that I might yet not know").

He is also as sprightly as ever, lifting spirits with upbeat songs such as the rollicking, boogie-woogie Early Days, an earnest tribute to the beginnings of rock 'n' roll.