We know very little about the Earth's natural cycles and the effects we have on them, so we are very far from knowing whether things are going in a good* or bad direction.
* Good for everyone involved, such as humans, animals, plants, etc.
Seriously though, it's very certain that global climate change of unpredictable magnitude right now is not desirable. The key problem is that we're not prepared to preserve biological diversity.
We're placing our ecosystems under extreme pressure, severely compromising them, sometimes depleting their resources so they will take hundreds or even thousands of years to recover. This results in mass extinctions and near-extinctions (which can be very damaging through genetic bottlenecks, aka inbreeding). For most species, we currently have no adequate technology to preserve single individuals, let alone entire populations, outside their original habitat.
Why does this matter? Because biological diversity is critical to our long-term success in bioengieering, and mind-bogglingly hard to replenish in an accelerated way. We will be able to preserve and resurrect species much sooner than we will be able to mutate them in a natural way to preserve their intraspecies diversity. But so far we can't even do that, so we're losing entire genotypes forever - genotypes that we have no idea how to reconstruct, or what hidden treasures lay in their genomes.
And this is just the biggest problem, not taking into account the philosophical preservationist argument, or the smaller problems like increased risk of global conflicts due to mass displacements, ocean acidification, etc.
Secondly, the effect of this 'mini ice age' will last a scant 10 or so years. Call me crazy but it doesn't make sense to burn more fossil fuels and continue to cause potentially unrepairable harm to our environment to optimize for a period of 10 years of relatively cool temperatures.
If the scientific community agrees that warmer temperatures are in the planet's best interest, I'm sure there is a safer and more effective way to bring that about then the massive amount of pollution and CO2 we are currently pumping into the atmosphere.
probability = ??????
probability = 0.50Of course stopping there seems to be silly since I'm sure more informed people have evidence that can shift that probability one way or the other.
So given any question where you know absolutely nothing at all about it, the probability the answer is "Yes" must be 50%!
It's just like if there was a stock the market know nothing about, but you know it just scored a magnificent deal a couple of hours ago, the market will see it as "meh, 50 50" (no price change), while you see "100% going to go up, must buy."
That's called insider trading, however. ;)
A sane risk assessment number should be something like:
Gain / (Risk * Damage)
So if the, theoretical, damage on Earth could make it something like Mars, we should act, even if we loose a lot of gain, that is comfort, and though the risk might seem low. On a sight note, the same goes for other humanity threatening dangers, like big asteroids.