It is precisely the very recent deviation (since 1975) from the natural cycle that demonstrates that the current conditions are not driven by the same old astronomical cycles. These cycles are inevitable. But, climate change is occurring far more rapidly now than at any time in the past 800000 years. Note that the Vostok ice core record you linked to is at a scale that simply cannot show the industrial revolution, let alone post-1975.
What that graph shows is the 100000 year Milankovitch Cycle. Again, you need to read more carefully because I just did explicitly tell you why the peaks are different. I will do it again in more detail:
There are feedbacks between T and CO2 that make the relationship sensitive and unstable. CO2 can cause warming, which causes outgassing of CO2 from the oceans, and CO2 affects plant growth which for some plants causes them to sequester more CO2, and for others, possibly the opposite. It is way too interdependent to expect a world with a particular flora and distribution of oceans to react exactly the same way 100000 years later when there is a different flora, and different oceans.
As to the overarching question. In the long term, there is no stopping climate change. There is no stopping dramatic climate change. Rate of change is everything. I posted this on the Palin vs. Gore thread, so sorry to everyone for the repeat, but it answers Sawzaw's overarching question:
A static environment is not the goal. We realize that this is impossible. Earth processes will never allow this. Climate has changed in the past, and uniformitarianism assures that it will change in the future.
The issue is not "change" versus "no change". It is "change on a geologic timescale" versus "change on a human time scale". "Natural" climate change is typically slow, proceeding at a pace that allows flora and fauna to adapt or migrate. Yes, there have been sudden global climate changes in the past. And, every one that we know of is associated with a mass extinction event in which the contemporary dominant genera disappear (and Homo is certainly among the modern dominants).
Today, climate is changing, and at a pace never before seen in the geologic record. There is good evidence that human activities contribute to this pace. How shall the world's flora and fauna react? It is proceeding too fast for evolution to help us adapt. The world is too full of anthropogenic barriers to allow sudden mass migrations. So, the response of Earth's biota cannot be uniformitarian.
Shall we throw up our hands and admit that we are quite possibly fuct?
Or, shall we acknowledge the possibility that we are contributing to the pace of climate change, and try to slow it?
Or, you may suggest something else.
A lot of people are simply in denial because trying to slow the pace will certainly have a dramatic effect on their lifestyle. They rationalize this by saying that the science is uncertain or even flawed. But they are not exercising the Precautionary Principle that they use in all other aspects of their lives: If there is baby formula with a 1% chance of causing adverse effects, we would all stop using it immediately. So why, in this instance, are we insisting on 100% certainty that we are harming our babies before we stop? **