Schalk we approach the planet's hard physical limits by not implementing the right kind of renewable energy.
Approximately 90 percent of the heat accumulated due to global warming has gone into the oceans and as seen in the following diagram the bulk of this heat accumulates about the equator.
The second law of thermodynamics states that an isolated system, if not already in a state of thermodynamic equilibrium, spontaneously evolves towards it.
Another way of putting this is heat moves from the area of warmth towards the area of cold until a state of equilibrium is attained.
It is clear from the diagram and experience that the coldest regions of the planet are at the poles. To move heat from the equator towards the poles, Nature relies, in part, on the first law of thermodynamics: heat and work are forms of energy transfer. Energy is invariably conserved, however the internal energy of a closed system may change as heat is transferred into or out of the system or work is done on or by the system.
Nature converts some equatorial heat to mechanical energy in the form of tropical cyclones and from the top of the cyclone heat radiates away from the equator towards the poles.
Unfortunately, this process works against mankind. Tropical storms cause death and destruction and the heat moved towards the poles melts the icecaps causing sea levels to rise more that they are already due to thermal expansion.
The permafrost also melts releasing tons of the greenhouse gases methane and carbon dioxide in a potentially catastrophic feedback.
Besides the poles, another massive cold sink resides on our planet in the depths of the ocean as shown in the following diagram.
In accordance with the second law of thermodynamics ocean surface heat is mixing with the cold water heat sink and a recent study indicates this is happening more rapidly than was expected. To the extent it may have masked the amount of global warming that was occurring over the past decade.
Ocean thermal energy conversion accelerates the movement of sea surface heat to the depths and converts some to mechanical energy. It turns cyclones on their head and in so doing prevents the movement of massive amounts of tropical heat towards the poles with damaging consequences and positive warming feedbacks.
The water holding capacity of air increases by about 7% per 1°C warming, which leads to increased water vapor in the atmosphere.
If there is a 1°C change caused by CO2, water vapour will cause the temperature to go up another 1°C and when other feedback loops are included, such as increased evaporation, the raising of cloud levels and melting of permafrost, the total warming from a potential 1°C change caused by CO2 is, in reality, as much as 3°C.
Since such an increase puts us in potentially catastrophic circumstances it is imperative that both CO2 and water vapour levels be maintained at or below current levels.
Only one form of renewable energy accomplishes this.