There are three distinct positions when it comes to the human-induced global warming debate:
1 Human-induced GW is happening but it is not a cause of immediate grave concern
2 Human-induced GW is happening and it is a cause of immediate grave concern
3 Human-induced GW is not happening
I find it worrying that the various advocates of these 3 various positions tend to focus their debate on very short-term factors. The debates typically focus on such factors as:
A Has there been an increase in extreme weather events due to human-induced global warming?
B Was the massive hurricane last month due to human-induced global warming?
C How much of recent temperature changes are due to 'natural variation' and how much are due to 'human-induced' effects?
D Is the atmospheric temperature likely to rise over the next 5 years due to human-induced global warming?
These questions have one thing in common. They focus on the present, the immediate past, and the very near future. The problem is that this approach is quite inappropriate when it comes to the phenomenon of human-induced global warming. Why is this? I will try and briefly explain.
The brief answer is: time lags and timescales.
A slightly elucidated answer: the biogeochemical cycles of the Earth have been 'carbon perturbed' to a massive degree but the effects of this perturbation will not start to become manifest until the second half of this century.
*** In other words, all of the above questions (A-D) at best completely miss the point, and at worst are of trifling insignificance and are dangerous because they distract attention from the real global warming problem that we face.
A slightly longer answer:
i) The atmospheric temperature of the Earth has been favourable for life for so much of the Earth's history because the increasing amount of solar radiation reaching the Earth from the Sun (non-human-induced global warming) has, until very recently, been offset by an increasing amount of carbon being stored under the surface of the Earth (as 'fossil fuels').
ii) Very recently humans have upset this long-standing atmospheric regulatory process. The temperature of the Earth has only been favourable for life in the recent history of the planet because so much carbon had been stashed away under the surface of the Earth. Humans have released an enormous amount of this stored carbon and released it back into the cycles at the surface of the Earth. This means that all of this carbon can now exert a very large warming effect on the atmosphere.
iii) The effects of this enormous release on the atmosphere are not immediate. The released carbon first enters the ocean and most of it finds its way into the deep ocean thermohaline circulation. Since the start of the industrial revolution most of the released carbon has simply entered this deep ocean circulation and none of it has re-emerged yet. The carbon is simply slowing moving through the deep ocean. A slowly ticking atmospheric time-bomb! It won't be until the second half of this century that the massive amount of carbon that humans have extracted from below the surface of the Earth will start emerging from these deep ocean currents. When this carbon starts to 'pour' out of the ocean a very significant increase in atmospheric temperature can be expected.
iv) Concentrating on the question of whether current / past / immediate future climatic events and temperature variations are 'natural' or 'human-induced' completely misses this bigger picture. The bigger picture is all about time lags and longer timescales.
v) The climatic regulatory system [i) above] has been massively perturbed and the effects of this have not yet become manifest, and will not become manifest until the second half of this century.
So, when we realise all of this the question becomes:
What do we do?
Well, clearly, reducing carbon emissions is not going to solve the problem. Reducing current and future emissions is a good thing, but it is not going to solve the problem that we face. The massive perturbation will not be offset by slightly reducing the amount by which we continue to perturb the system! The only thing that we can do is to be as technologically prepared as possible. By the second half of this century we can be in a position which enables us to be technologically proficient at pulling carbon out of the atmosphere. This is the only way that we can restore the long-term atmospheric regulatory system [i) above] to a state of short-term balance. When the carbon starts gushing out of the ocean we simply start pulling carbon out of the atmosphere.
In fact, the sensible option would be to start pulling lots of carbon out of the atmosphere before the massive store of carbon in the themohaline starts to gush into the atmosphere.
Is all of this a 'good' or a 'bad' thing?
By posing this question I want to get you thinking about the even bigger picture. This technological solution will only put the long-term atmospheric regulatory system [i) above] back to a state of short-term balance. The problem is that this regulatory system cannot last forever because there comes a point when the carbon in the atmosphere runs out! What this means is that the future existence of life on the planet requires a longer-term technological solution. The increasing solar output of the ageing Sun needs to be directly intercepted before it reaches the Earth's atmosphere. This is the only way that humans and other 'interesting'/'complex' life-forms have a long-term future on the planet.
So, in brief, given that the survival of life on the Earth is a good thing, this means that the development of the human capacity to technologically regulate the atmosphere in various ways (both pulling carbon out of the atmosphere and directly blocking incoming solar radiation) is a very good thing for life on Earth. The short-term human carbon perturbations are a side-effect of becoming technological and also the stimulus which catalyses the technological development which all life on Earth needs in order to survive.
So, all of this is an exceptionally good thing!
There is much more detail on all of this in my books.
In my first book I paint the broad (technological) picture of humans in the cosmos and how this relates to environmental issues:
I go into more detail about the nature of the universe and the perturbation of the biogeochemical cycles in this book:
An Evolutionary Perspective on the Relationship between Humans and their Surroundings: Geoengineering, the purpose of life & the nature of the universe
And, in this fairly short book, I make the case that the human species is obviously the saviour of life on Earth, rather than the destroyer (which is the most popular contemporary view):