Once upon a time, let's say 20 years ago, people were aware of something called global warming, but there seemed no awareness of what that meant. At least in the UK, possibly even in Europe and the USA. We enjoyed warmer summers, but changes in the weather patterns went unremarked. There were optimistic tales of improved English wines. There was, perhaps, a dark underside to the whole thing, but it was outshone by the silver lining. We could convince ourselves that all was well, even though we might glance over our collective shoulder from time to time. The shadow loomed gradually larger, of course, as news leaked out about possible impacts, governments began to have discussions and the IPCC¹ became part of the landscape. No doubt the many scientists working on the matter had other views, but the general reporting remained somewhat hopeful, and, with hindsight, global warming was generally down played.

Some people knew what was going on though. There has been a continuous stream of denials that are more clearly related to fear of the dark shadow itself², but there are also denials from organisations that are funded by very rich people³. This is straightforward raising the drawbridge - global warming is clearly real enough to mean loss of money, and that cannot be allowed to happen.

So what is going to happen? Where to start ...

Global heating better describes what is going on and it has a number of impacts:

• The rise in global average temperature disrupts the stable climate, giving rise to much greater extremes of high and low temperature, changes in rain patterns and changes to wind patterns such as the periodic El Niño. These changes do nasty things to our living environment:

  • The extremes of temperature and changes to rain patterns mean we will not be able grow food. Hot places will get hotter, dry places will get drier, and agriculture will become impossible.
  • The extremes of temperature will make hot parts of the globe uninhabitable for humans - and animals and plants.
  • Changes to wind patterns will alter the distribution of volcanic dust, reducing fertility.

• The rise in global average temperature melts ice fields and warms the oceans:

  • No ice means sunlight is no longer reflected away, accelerating the heating process.
  • Warmer oceans means changes to ocean currents. The Gulf Stream, as one example, will close down, or, at least, change course, and the British Isles climate will no longer be temperate and stable.
  • Melting ice, and warmer water, means rising sea levels. Low lying coasts will be inundated and land for living on or growing things will be lost.

• The rise in CO2 content in the atmosphere means more CO2 in the oceans. Dissolved CO2 is acidic and many sea creatures cannot live at the new levels of acidity:

  • The resulting loss of biodiversity means no fish for us to eat.
  • The loss of biodiversity also disrupts the oceans ability to recycle natural runoff from the land - the oceans become ever more polluted and unusable.
  • Dead oceans are not able to absorb CO2 and cannot contribute to the normal CO2 cycle.

• The rise in CO2 content will initially encourage trees to grow, but only up to a point. Too much CO2 inhibits growth and closes down this path in the CO2 cycle.

The result, for us, is ever increasing social disruption as people flee from rising water, migrate in search for food, and search for a land with survivable temperature extremes. The increasing pressure on what is left will result in war.

The report, SR15, is the hardest hitting report so far produced by the IPCC. It says we have a good change of surviving if the global average temperature is kept to below 1.5°C above the pre-industrial level, and that this temperature is likely to be reached between 2030 and 2052 "if it continues to increase at the current rate". Ok, that sounds hopeful, maybe. There will still be problems, but we have some time to reduce our emissions, make sure we have an appropriate approach to growing food, and sort out social structures and institutions that can cope. After all, we have an agreement now between governments that addresses these issues, so work is in progress.

Let's hope so, eh?