It's not going to happen. Labour need to put funds towards fixing the NHS and other state services systems that have been systematically dismantled by the conservatives.
With America isolating itself times are uncertain so funding has to be set aside to deal with inevitable turmoil.
Finally, European nations need to decide whether to accept America handing Ukraine over to Russia or if they continue to support Ukraine. Even if Europe withdraws resources from Ukraine there needs to be a reassessment of military spending because NATO doesn't look particularly reliable right now.
There simply won't be anything left to pledge towards a climate revolution.