This is an absurd take... Russia emits 4.65% of world output and has been decreasing last year the most out of the top 10 [0]. Could you base your arguments? I'd like to understand where this is coming from.
[0] https://www.worldometers.info/co2-emissions/co2-emissions-by...
https://climateactiontracker.org/countries/russian-federatio...
More generally, if Russia (or any party) has incentive, means, motivation to create climate change, do not be surprised if they actively work to make it happen. Russia can literally light things on fire and come out way ahead.
Geopolitically, it benefits from additional pressure on Europe to accommodate the migrations caused by climate change, and all the instability it causes.
You know what is even worse for farmers than a cold climate? An unpredictable one. It's damn hard to pull a profit farming if you can't rely on any kind of 'normal' growing conditions from year to year.
An increase in mean temperature isn't a neat and tidy "oh, we'll just move north"; it's on the whole an increase in variance.
I'm seeing it happen here in Canada, and I'm certain we'll see it in Siberia as well.
In the end, petro-regimes like Russia, Venezuela, Saudi Arabia, Alberta, whatever... they'll become more and more paranoid and erratic and dysfunctional as the broader crisis around 'energy' deepens. We're right now seeing our first war triggered by a cornered petro-regime on the cusp of climate catastrophe. I suspect we'll see more.
It takes more than a change in temperature to make land useful. I don't think recently-defrosted tundra is going to suddenly be profitable farmland. You need the right soil type, weather, irrigation, transport links, workers, energy sources, etc.