Bazz,
No, the 50% figure doesn't strike me as improbable. The evidence is overwhelming!
The 280ppm figure is well accepted, and nobody has come up with a credible alternative claim. Importantly, calculations based on fossil fuel use show human activity has released far more CO2 into the atmosphere than it would take to increase the amount in the atmosphere by 50%; more CO2 has gone into the ocean than come out of it.

Ottmar Edenhofer has been frequently misquoted in denialist propaganda, and his unsympathetically translated quotes (the original was in German) have been taken out of context to fool people into believing he was using climate policy as a smokescreen to achieve the outcome of redistributing the world's wealth. But if you read what he said in context it's clear he's actually emphasising the importance of development policy to achieve environmental objectives.

But don't just take my word for it; read it yourself: http://translate.google.com/translate?hl=en&tab=TT&sl=de&tl=en&u=https%3A%2F%2Fwww.nzz.ch%2Fklimapolitik_verteilt_das_weltvermoegen_neu-1.8373227

And that doesn't strike you as improbable ?
Another suggestion is that the co2 increase since the 18th century was
caused by the warming after the mini ice age releasing co2 from the ocean.
This increased co2 has been suggested to explain NASA's finding that
the earth has been greening significantly.
The current cooling fits in with the current low sunspot count.
This will I suspect be short term cooling but coincides with Svenmark
and the Turku & Kobe findings. The real cool time according to some
should be around 200 to 300 years time as that is the Medieval warm
period cycle.
Well we won't settle that here but it is enough that there are a lot
more factors than what has generally been accepted.

No, Olever90, it doesn't strike me as improbable. In fact it strikes me as highly probable – very very near certain. What exactly is it that makes you think it's improbable?

>Another suggestion is that the co2 increase since the 18th century was
>caused by the warming after the mini ice age releasing co2 from the ocean.
Who suggested that? It can be completely ruled out: we know with absolute certainty that it was caused by combustion of fossil fuels. Why do you have so much trouble comprehending that?

>This increased co2 has been suggested to explain NASA's finding that
>the earth has been greening significantly.
Yes, and it is likely to be a major factor in that.

>The current cooling fits in with the current low sunspot count.
What current cooling? Globally this is so far looking like the second hottest year on record (after 2016). Were it not for your next claim I might have taken you to mean the cooling caused by ocean currents, though I don't think that has much to do with the sunspot cycle.

>The real cool time according to some should be around 200 to 300 years time
>as that is the Medieval warm period cycle.
Now THAT strikes me as improbable!
Why do you base your views on dubious cycles rather than the major factors that are known to change the climate?