The UN's World Oceans Day really shouldn't be necessary - at least not in this context. Earth, sea and sky - our three ancient realms. Three of the four great 'elements' that define our existence polluted beyond recognition and to the point that they are making life rapidly extinct. So a day to remember and consider our oceans is most necessary.

But we must do more than just think. We must act.

Stop buying stuff in plastic. Say no to the clothes that pour non-biodegradable microfibres into our water when we wash them.

And it is wider than the direct impact of plastics.

Our seas are heating up so stop flying and start campaigning for better public transport. Walk places too. I have pledged not to fly again. Will you simply pledge not to fly in 2020?

Here in the richest part of the world, the top 10%, we are responsible for half of the world's emissions. The poorest half - yes half - of the world account for just 10% of CO2 emissions. If in the UK we live as though there are five planets and therefore need to reduce our impact by 80% (I suspect the figure is probably 90%) then we can still do that and still be in the top quartile of wealth.

Our lives are extravagant - we need to find a new way of living.