I'm a simpleton really, I go for simple explanations for what is happening.
Basically we have a climate that reflects that we are in an interglacial period of an extended great ice age. Interglacials typically last 10-15,000 years. Ice at both poles (that won't change for the forseeable millenia due to the proximity of land to the poles) causes the climate to vary by the permanent warm to cold air and water flow. Political activists want us to believe that climate variation, also typical of interglacials, is being driven by human output of CO2. Here are some facts. CO2 is what plants are made from. It is their food source. CO2 levels control the amount of green stuff on the planet, more means more and less means less. NASA scientists showed that biomass has been increasing globally around 1% every 3 years, habitat area for animals is increasing. That shows that we are not at an optimum level yet. That crops are returning increasing yields (without suffering nutrient deficiency) shows the brainlessness of stifling emissions. Warming has at no time been alarming.
What is the basis for politicians, business, financial institutions and various extreme environment groups for claiming humans are influencing the climate harmfully? They claim our adding 1 molecule of CO2 to nature's 12 per 100,000 molecules of atmosphere every 5 years drives warming and if it continues we will have runaway warming. I have a number of problems with that claim.
1. It was made based on 13 years of warming following 33 years of a cool period.
2. Temperatures before the cool period were as warm as recent times and there was a cool period preceding that time.
3. There was the Little Ice Age up to the beginning of last century and without warming we would still have freezing conditions.
4. There was no acceleration of warming that would indicate increasing CO2 levels (from all sources) was influencing the climate.
5. CO2 is not a heat producer, it can only influence what is there, i.e. it can keep it warm fractionally longer. It can't raise the temperature.
6. Because of its slow and steady increase, CO2 is incapable of causing sudden events that have been attributed to human emissions causing warming.
Protagonist scientists admit CO2 alone has such a minor effect on temperature taken alone that it must act through a convoluted feedback where its effect is magnified by causing more water vapour to be produced. The first problem with that is that it is conjuring more energy from less and that is just not possible. The second is that water vapour increasing means more cloud (NASA showed it produces low cloud) and that means less sunlight, more rain. The third is that water in the atmosphere is self-limiting due to its ability to change state from gas to liquid.
The IPCC as the main protagonist and propagandist has produced a succession of assessments. This is because each assessment was fundamentally wrong necessitating a reassessment. They still haven't got it right. We are paying for these boondoggles.
The claims made by the IPCC are not based on science or observation, they are based on modelled projections of the climate. Models are very weak for a variety of reasons. Not least is that it is impossible to model the climate. The best they can do is to produce a flat Earth without North or South Pole, without the Tropics, without clouds and bathed in a 24 hour haze of sunshine. That they are useless as predictive tools was heavily emphasised by the total failure to anticipate both atmosphere and oceans cooling. The original output that was used to frighten politicians into becoming green activists consisted of three scenarios, business as usual producing increasing volumes of CO2 gave very alarming temperature increases, less but still higher than natural increases if some reductions were made and a (best case) low, natural increase if all human CO2 emissions were returned to pre war conditions. Well, we saw only escalating CO2 levels and the temperature did what? It came closest to the best case scenario, trending below it. Not only proof that models are useless for predicion but that the assumption that CO2 drives the climate was proven totally baseless by the climate. We saw "global warming" stop in 2001 and reverse in 2007.
Average global temperature has increased around 0.5 deg C per century since it started to climb during the LIA, around 1850. Last century saw an increase between 0.4 and 0.6 C that is well within expected natural variation. This century may see a similar increase or it could continue to cool. The fact is NOBODY KNOWS.
Oceans more acid is a bad joke. Around 1% of absorbed CO2 is chemically changed by the oceans, a fraction of the 1% goes to making acid. The human contribution amounts to less than 1 part in 600 million per year. Oceans receiving increasing amounts of real pollution is a major problem but seems to be of little concern to the nut jobs frantically complaining and ranting about the climate becoming nicer and blaming us for it. Well it was but that seems to be history now. It's well past time the IPCC, the UN, the media circus, power befuddled politicians and rent seeking scientists followed the climates lead. History will not be kind to them.
Scientific take down of models.
Scientific take on anthropogenic climate change