1. The basic physics
2016 was claimed as the “hottest year ever”. Well, the hottest for a few centuries, anyway, if the global temperature measures are to be believed. Let’s suppose that they are. It is known that 2016 was an El Niño year, and that the “hottest year ever” was caused by a burst of warm water from the ocean (and we know that CO2 doesn’t act that fast). So – where did the El Niño’s heat come from? Let’s look at some basic physics:
Greenhouse gases (GHGs) warm the atmosphere. From there, the downward Infra-Red (IR) radiation reaches the ocean surface.
IR cannot penetrate more than a fraction of a millimetre into the ocean, so it warms just the surface skin. From there most of its energy goes back into the atmosphere or space, but some of it can convect or conduct into the ocean. From the 2nd law of thermodynamics, in the absence of work, net heat transfer can only occur from a warmer object to a cooler one. So …
- The atmosphere cannot warm the ocean surface skin to a higher temperature than itself.
- Water in the ocean surface skin cannot mix with deeper water to create water of a higher temperature than itself.
- Water from the ocean cannot warm the atmosphere to a higher temperature than itself.
This means that none of the extra warmth from the ocean which caused the “hottest year ever” can have come from GHGs within the last few centuries. It’s not a question of how much came from GHGs and how much from natural causes. The proportion of the extra heat that actually came from GHGs (within the last few years at the very least) has to be precisely zero.
The basic physics tells us: The atmosphere cannot heat itself !