You cannot match up pro and con-climate change scientists 1-1, actually, it is a very small minority of scientists that reject man-made climate change, and even fewer that reject climate change. Search the scientific literature. As a non-professional you would do wise to trust the scientific consensus rather than the lone loonies.

Scientific discussion goes on how big the impact will be, not the ifs, nor the whys.

Since the start of the industrial period there has been a steady growth in the concentration of atmospheric CO2 of about 30%. This growth cannot be ascribed to natural processes or special events such as volcanic eruptions. The latter would show as clear sparks. If natural processes were responsible we should be able to track them down right? There is no discussion that this change can be directly ascribed to human activities.

Also, there is no discussion that CO2 is a greenhouse-gas, you simply look at the absorption spectres, CO2 absorbs frequencies that would otherwise not be absorbed by other atmospheric substances.

It is also fairly easy to figure out if this comes from current biological processes, for example destruction of forest or from burning of fossil fuels, simply by monitoring the ratio of C-14. Ice core studies have provided samples of air from pre-industrial times trapped inside the ice for centuries. This gives an indication of CO2 level without human activity and the concentration of C-14 when the earth is in natural balance. Now, destruction of forest produce high concentrations of C-14 while fossil fuels produce CO2 with almost no C-14 as the C-14 has decayed over millions of years.

This shows that a significant part of the CO2 increase comes from burning of fossil fuels, and can only be ascribed to human activities. AFAIK, no other species on this planet burn fossil fuels. Another significant part can be directly ascribed to the deforestation, also a human activity. The main problem in this is the lack of historic records of forest cover, in particular pre-space age, so it is not possible to estimate exactly the rate of deforestation. (you may get an estimate of the deforestation if you assume that the remaining change in CO2 concentration is ascribed to deforestation).

There is very little room for doubt in the above, it all is well understood. The conclusion is, human activity is directly responsible for the main growth of the atmospheric concentration of greenhouse gasses. Further, the concentration of greenhouse gasses can be correlated to the increased average temperature.

The uncertainties comes in determining how the different systems interact and what will happen in the future on local and global scale. For example, if the polar cap disappears the albedo will decrease and more light absorbed leading to further heating. The polar cap has been decreasing rapidly only recently - the average temperature in that area has to hit 0C for the process to start. This means that things may change at increased rate.

To model this historic records of climate and atmospheric constituents obtained from ice-core studies allow us to run models on known data to calibrate the different parameters. Then run the model on current data to make predictions about future climatic change. This is ongoing science, this is where the discussion is and has been the last decades. But models have become better, more powerful computers allow us to include more details and calculate more accurately. But all models so far indicate global warming.

There is little discussion that the Earth pretty much did well on its own in pre-industrial times. A pre-industrial climate would provide us with a fertile Earth and stability for the benefit of human civilisation. It is interesting to note that human civilisation has arisen in a time of unprecedented climatic stability! So, we have a clear long-term interest to preserve this. Certainly, life on earth will proceed, also after we screw up and disappear.

It is true that people like simple explanations to complex phenomena, but most people don’t even observer climatic change and never will. They have no need for an explanation of a problem they don’t see. It is BS to claim that global warming is the simple convenient explanation.

Politicians have no advantage assuming global warming, it may only mean more expenses to account for - they’d be more popular spending taxes on anything else, as mentioned previously. After all, that’s what insures re-election.

Hence, there is little to promote the theory of global warming except facts. You would do wisely to study the facts. Trust those that are brighter than your self, not the loonies - always worked for me.

What I explain in this article is against the general belief that we are experiencing unusual climate exchange, and that it’s caused by human activity. So, in that sense, yes, I try to promote uncertainty about something we are told to take for certain, and I would like that more and more people start doubting that what we are told is true.

Granted, it is incorrect that Earth would freeze when the Sun dies. It will simply be destroyed. But the point was that if the source of heat wasn’t there, it would be frozen. My point was to highlight the fact that the temperature on Earth is due mainly to the Sun.

While I do not have a degree on physics, and however solid the science may be, humans do not know everything.

It is basic human nature that humans rush to believe anything they are told which may easily explain something which is otherwise unexplainable.

Man-made climate change is a case of this: It is much more comfortable to think that climate change is here, and is caused by humans, than to think that global warming is part of a cycle of Earth, or that it’s due to changes in solar activity, or, more importantly, something else which we do not know about.

I do not claim that climate change is not real. It may be truly there. This I do not know. But to say that it is man-made is a different story. You know very well that Earth has gone through many different periods of climate changes. Humans don’t know exactly why they took place, but we know they did take place. What we see happening on Earth in the recent years may very well be part of the lifecycle.

How can we claim that humans are responsible (in part or in whole) for the current changes? What is the conclusive evidence? For every scientist that claims that humans are the cause of global warming, you can find another scientist denying such theory. The “10,000 most respected scientists” may be very respectable, but what about the other scientists? I am not saying let’s go with the other ones, but I say that there is sufficient doubt.

Given this doubt, I claim that we cannot believe that climate change is human made.

My assertions about how small humans are compared to the Earth system and to the system it lives in do not have a scientific base, granted, but they do not intend to be a scientific explanation.

You point out that research which concludes that global warming is not man-made is funded by industrial groups with interests in promoting such views. Then, if this is so, why do we have to blindly believe that the other 10,000 scientists do not have their own interests in promoting their views as well?

Again, I want to highlight the humongous room for doubt, and there is no stupidity in lack of trust over this or that group of scientists.

Hmm… I didn’t claim that Governments spend funds on propaganda rather than science. I claimed that the science they fund is necessarily ‘encouraged’ to produce results that support the theory that humans produced the global warming we are seeing.

I think that inadvertedly, you may have hinted at one very important point in your explanation about climate studies. You mention that the changes “observed” “show” [...]. This is exactly the problem: we know what we have observed, and what we have been able to infer from those observations, but we do not know that this body of knowledge about the Sun, or about climate, is really comprehensive.

With time, mankind has always made new discoveries, often proving previous beliefs to be wrong. This might very well be the case once again.

Finally, I think you’ve taken some ironic comments in my article a bit out of context, or maybe my language did not convey the intended sarcasm: I don’t speculate about other stellar objects further away than the Moon or the Sun, so be sure that my comments did not rest on astronomy.

It is FUD when you claim that governments have an interest in supporting science that will justify subsidising marginal industries, any politician would gain much more popularity short term by lowering taxes or improving health care, education, childcare ore eldercare, while industries may have political interests, they don’t have a vote, it is much more profitable to answer directly to the interest of the general public. Further politicians usually think short term, the next election is at most 4 years away, answering current short term concerns is much more profitable for the polls than trying to build popularity on climate change hype. Also, fighting wars is usually the dirty trick to get re-elected, people fear changes when the nation is at war.

Finally, no politician AFAIK has played the obvious fear trump to promote action against global warming: All simulations show climate changes will hit more severely in the extreme environments, in Africa this will cause famine and mass migration. So, to front immigration pressure, global warming must be addressed. This is a cheap and easy argument, yet no one use it.

Government funded fundamental research should be independent of conclusions needed for any given policy, and fact is that funding has been taken from research that conclude global warming is human made, and fact is that politicians have edited and changed scientific documents supporting man made global warming such as to conclude the opposite, or leave the document inconclusive, in order to justify passivity. In no case has the opposite been reported.

It is interesting, in contrary, that the main research that conclude either global warming does not exist or that it is not caused by human activity, all receive significant funding from industrial groups that have a direct and clear interest in promoting such views.

So, your conclusion that you should not trust 10.000 of the world most respected scientists in the related areas is sheer stupidity.

Claiming that government funds are spend on global warming propaganda rather than science is simply FUD.

The sun theory has been studied extensively and been disregarded. In fact solar activity is closely monitored 24×365 for astronaut safety, solar flares are lethal for astronauts. The contribution from the sun as well as contributions from other objects such as the moon are extremely stable and easy to calculate.

Ice core studies and studies of sediments, tree rings etc. have given a detailed history of the suns activity correlated to climatic changes. Regular observations of sunspots have been done since 1749, and irregular observations date back to 1610, with the first observations by Galileo. The conclusion is that while the 11 year periodic changes observed in sun spot activity does show short term climatic changes, there is no evidence for significant changes in sun activity that can be correlated to and account for the climatic change seen over the past 200 years.

Your speculations about other stellar objects influence on the Earth climate are as ridiculous as the astrologers claim that position of distant planets or even stars affect our destiny. It’s time you go back to university before making such ridiculous statements and spreading FUD.