"People later thought that Arrhenius's prediction that atmospheric carbon would increase was wrong, because they thought that oceans would serve as great carbon sinks. It would be interesting to look into whether they had good reasons for thinking this at the time."
The oceans contain about 50× as much CO2 as the atmosphere, and they're estimated to be removing CO2 from the atmosphere about 1/4 as fast as mankind is adding it. (The terrestrial biosphere is also estimated to be removing CO2 from the atmosphere, through "greening," about 1/4 as fast as mankind is adding it, so if anthropogenic CO2 emissions fell by more than half then atmospheric CO2 levels would be falling, rather than rising.)
So, the principle was correct, it's just that those "negative feedbacks" are not keeping up with the high rate at which mankind is emitting CO2.
"Arrhenius predicted that global warming would have positive humanitarian impacts on balance, global warming now appears to have negative humanitarian impacts on balance. "
No, Arrhenius was right even about that.
The best evidence is that manmade climate change is benign, and CO2 emissions are very beneficial, for both mankind and natural ecosystems. I’m one of over 30,000 American scientists who’ve signed a “petition” attesting to that fact.CO2 is “plant food.” Are you old enough to remember when terrible famines were often in the news, in places like Bangladesh? Throughout history, famine was one of the great scourges of humanity, the Third Horseman of the Apocalypse... until now.Thankfully, famines are becoming rare, and one of the reasons is rising CO2 levels, which have increased worldwide agricultural productivity by about 20%.
If we lacked that additional productivity, mankind could approximately make up the difference by putting all of the world's rainforests under cultivation.Those benefits are well-measured, by thousands of agricultural studies. The supposed major harms are all just hypothetical.
Rising CO2 levels not only make plants healthier and more productive, they also make them more water-efficient and drought-resistant. One of the consequences is that the Earth is "greening," especially in some arid regions, like the Sahel (southern Sahara), as reported in National Geographic:https://www.sealevel.info/Owen2009_Sahara_Desert_Greening-atGeo30639457.htmlEXCERPT:“Images taken between 1982 and 2002 revealed extensive regreening throughout the Sahel, according to a new study in the journal Biogeosciences. / The study suggests huge increases in vegetation in areas including central Chad and western Sudan. ...“’Before, there was not a single scorpion, not a single blade of grass,’ he said. “’Now you have people grazing their camels in areas which may not have been used for hundreds or even thousands of years. You see birds, ostriches, gazelles coming back, even sorts of amphibians coming back... The trend has continued for more than 20 years. It is indisputable.’”
We are currently enjoying what has traditionally been called a "climate optimum." It is generally acknowledged that the Earth has warmed, on average, about 1°C (±0.4°C) since the "pre-industrial" Little Ice Age, and it is also generally acknowledged that the warming has been beneficial. Yet activists claim that warming more than another 0.5 °C would be harmful, rather than beneficial. That claim is not based on scientific evidence, and is not credible.The direct impacts of global warming are obviously minor. Except at high northern latitudes, where "Arctic amplification" makes the brutal winters there a bit milder, we’re on track for at most about one degree of additional warming by 2100 (and even that assumes no large-scale transition to nuclear energy). At temperate latitudes, that’s like moving only about 70 miles south, or planting only about one week later.So folks promoting solar and wind boondoggles hype other supposed harms, like sea-level rise, or extreme weather, or polar bears' peril. But those problems aren’t actually happening.CO2 has been rising steadily for 2/3 of a century, yet sea-level rise has not detectably accelerated:
Hurricanes & typhoons are not worsening:
Strong tornadoes have actually declined:
And the polar bears are fine:
Here's what Arrhenius wrote:
Notice that he even predicted "polar amplification."
The best evidence indicates that he was exactly right.