5. Indirect consequences matter

In September, Harvard University announced it would divest from fossil fuel.

It took organisers 10 years to make that happen.

For more than nine years you could have looked at the campaign as unsuccessful, even though it was part of a global movement that got trillions of dollars out of fossil-fuel investments, recast the fossil-fuel industry as criminal and raised ethical questions for all investors to consider.

This month, Bloomberg News reported that the "cost of capital" for fossil fuel and renewable energy projects used to be comparable, but thanks largely to shareholder and divestment activists, the cost for fossil projects is now about 20%, while that for renewables is between 3% and 5%.

This affects what gets funded and what is profitable.

The campaign against the Keystone XL oil pipeline was, for many years, a jumble of wins and losses and stalls and setbacks – and then finally the pipeline was completely halted when Joe Biden came into office.

This was not a gift from Biden; it was a debt being paid to the climate activists who had made it an important goal.

Patience counts, and change is not linear.

It radiates outward like ripples from a stone thrown into a pond.