Carbon dioxide emissions over two centuries have produced massive benefits for humanity

See The great carbon boom by Indur Goklany, an independent scholar and author. He was a member of the U.S. delegation that established the IPCC and helped develop its First Assessment Report. He subsequently served as a U.S. delegate to the IPCC, and an IPCC reviewer. Excerpts:

"The plant-productivity increase has been steady, large and ubiquitous: widespread evidence confirms that the earth is greener; terrestrial ecosystems’ productivity has increased 14% since 1982. Further, the IPCC estimates that the terrestrial biosphere productivity is 5% over pre-industrial times, that is, “carbon fertilization” due to rising CO2 levels has helped overcome any productivity loss from deforestation and other habitat loss. (Habitat loss is the greatest threat to terrestrial biodiversity and natural ecosystems.)

Carbon dioxide emissions over two centuries have produced massive benefits for humanity — and nature. Halting emissions could increase hunger and  habitat destruction

This productivity increase is to be expected: the results of thousands of scientific experiments indicate that at current levels of atmospheric CO2, crop yields should increase by 9-15% relative to pre-industrial levels because higher CO2 increases rates of plant growth (i.e., photosynthesis), improves the efficiency with which plants use water, increases their drought resistance and, possibly, increases resistance of crops to pests and weeds.

These increases in crop yields, in addition to helping feed a larger population, have limited the need to convert existing habitat to farming. The increased crop yields from higher CO2 levels reduced habitat loss by 11-17% compared with what it would otherwise have been. Consequently, more land has been left relatively wild.

Satellite evidence also confirms that increasing CO2 concentrations have resulted in greater productivity of wild terrestrial ecosystems in all vegetation types. Moreover, increasing CO2 concentrations have also increased the productivity of many marine ecosystems, and although this effect may be partially or fully offset by the effect of lower average pH on calcification rates in some marine organisms, the evidence of net harm in wild marine ecosystems remains sparse."

"Empirical trends indicate that climate-sensitive indicators of human well-being have also improved markedly over recent decades, notwithstanding the gloomy prognostications of warmists.

The above-noted increases in crop yields reduced chronic hunger in the developing world from 24% of population in 1990–92 to 14% in 2011–13, despite a 37% increase in population. The increase in GDP per capita reduced the absolute poverty level in developing countries by almost three-quarters between 1981 and 2012 (from 54% to 15%). Between 1990 and 2012, more than 2 billion additional people obtained access to better sanitation and safer water. The global mortality rate for malaria, which accounts for about 80% of the burden of vector-borne diseases that may pose an increased risk due to global warming, declined by 95% since 1900. Deaths from extreme weather events have declined by 93% since the 1920s and, once the increase in the amount of wealth-at-risk is accounted for, there has been no increase in economic damages from extreme weather events.

The wide divergence between dystopian warmist claims and empirical reality can be attributed to the fact that those claims derive largely from unvalidated models. Empirical data, however, indicate that these models have overestimated the rate of warming.

A recent study compared projections from 117 simulations using 37 models versus empirical surface temperature data. It found that the vast majority of the simulations/models have overestimated warming, on average by a factor of two for 1993–2012 and a factor of four for 1998–2012.It also estimated that the observed trend for 1998–2012 was marginally positive, but not statistically significant; that is, notwithstanding model results, warming has essentially halted.

Impact models, likewise, have underestimated direct benefits of CO2, overestimated the harms from climate change, and underestimated human capacity to adapt which enables the benefits to be captured even as it also reduces the harms. Consequently, these models overestimate net negative damages.  Not surprisingly, dire prognostications of increasing death, disease, and decline of human and environmental well-being from global warming are not reflected in the empirical data."