I can think of seven different timescales in which changes seem to be happening right about now. Of course, you can probably take any point in time and construct such an edifice since everything is changing all the time, but this seems to be a moment in which it is particularly compelling to do so. Anyway, here they are.

100 year Political/economic cycle

This is the business cycle and associated political cycle which was apparent by the early twentieth century. In the 2016 US election the candidate with the highest approval ratings was Bernie Sanders whose policies all polled at 65 to 85% support. With the right-wing populist split within the Republican Party as well, this shows a clear reversal of momentum from the last 50 years.

250 years, industrialization/capitalism

Capitalism -- the rise to dominance of business over the feudal order -- began as small operations in a much larger world. Even after "bourgeois democracy" replaced feudalism capitalism still flourished within a colonial world order. Now, industrialization is everywhere and the carrying capacity of the planet for economic expansion has been exhausted. Capitalism must deal with the end of growth, and industrialization must deal with the absence of cheap resources and ready markets.

500 years, European domination

When Europe discovered it was in a position to rule the world, it immediately set about arranging everything to benefit Europeans. For instance, by 1700 it had worked out that black people and only black people would be slaves. Even after industrialization ended slavery the relative status of the different ethnic groups was preserved.
As recently as 50 years ago, the norm was to be a white heterosexual christian male and everyone else was considered a minority. So much so that the feminist joke that women were the majority minority actually made slightly startling sense. Today, those who still consider that norm to represent their cultural values are very much on the defensive (and aging).

2500 years, the beginning of dense population

In ancient times -- those of Babylon and the pharaohs and the Hebrew bible and Homer's songs -- people lived in small nations a separating distance from each. When the Persians conquered the whole of south central Eurasia it marked a point (and an enlightened empire) where people were suddenly thrown, if not together, then right up next to each other. It is at this moment that Confucius and Lao Tsu, Buddha and the Bhagavad Gita, Isaiah, and Thales and Heraclitus appear. The common thread being the common fate -- the move from the world being your own city, people, small empire to everyone living in a single world. All of these teachings were in part about revealing that. Now it is manifest and unavoidable.

10,000 years, domestication

Agriculture and herding first appear after the end of the last ice age. For the first time people were pinned down to fixed locations which allowed some to rule over others. As long as a group's domesticated space was small and there was still a larger wild nature outside of it, the very masculine project of protecting and expanding that space was prominent. Now we have domesticated the planet with the only "wild" areas left dependent on protection as parks. That we all live in the same house, so to speak, means that feminine energies of maintenance and continuity become at least as relevant as masculine ones.

100,000 human creative breakthrough

Sometime 50 to 100,000 years ago (early in the last ice age), humanity suddenly had a creative breakthrough with all manner of new utensils appearing and spreading -- needles (still in use today!), fish hooks (more like small harpoons), spear throwers, art (body painting, jewelry), etc. This is presumed to have "something to do with language" (more on that in another entry). Since then we have had a more or less steady increase in cleverness up to the present. Now, our cleverness itself is becoming our undoing. For the first time we can not use our problem-solving skills to solve a problem without immediately bringing on a cascade of other problems.

4 billion years, complexity

Very large things (like galaxies) and very small things (like atoms) are relatively simple.

It's the stuff in the middle that gets most complex (eg, the human brain is the most complex physical structure that human brains know of).

Similarly, according to the current story, the early universe and the end of the universe are much simpler than the ecology on our one small planet. The early universe was a great burst of energy and the end will be a completely even spread of dissipated energy. This is the time when energy is most constrained into self-organized systems. To be sure this period is billions of years long (or more), nevertheless, with all of the ecological simplifications humans have introduced on this planet we would seem to be at a local peak of complexity.