A simulated global warming of nearly 5°C will actually lead to more greening, more vegetation, more gross primary productivity…even if CO2 fertilization is held constant at present levels.
A 2021 observational analysis (Cortes et al.) published in Geophysical Research Letters indicated that since 1981 15.8 million km² of the Earth’s land surface has greened and just 1.1 million km² has browned (median). The observation mean results suggest 16.6 million km² of the Earth’s surface has greened and there has been “no browning” at all in the last 40 years.
Image Source: Cortes et al., 2021
It is widely accepted that rising CO2 concentrations have been the dominant driver of these global greening trends in recent decades.
“CO2 fertilisation is considered as the dominant factor responsible for the global greening phenomenon, contributing 70% of the increased global leaf area index (LAI) since the 1980s” (Liu et al., 2022).
The projections are for enhanced greening to continue unabated as CO2 concentrations double to 560 ppm by the end of the century (Wenzel et al., 2016).
And now a new analysis (Gao et al., 2022) suggests that even if the CO2 fertilization effect is held constant over the next 60 to 80 years, a global warming of 4.87°C will also result in even more net greening across the globe. The regions that are simulated to become browner are easily overwhelmed by the greening regions.
So when it comes to vegetation, leaf area, and gross primary production, the effects of rising CO2 and rising temperature are net positive.
This is likely not welcome news for those who wish to peddle climate alarmism.