Greening or warming?

Greening is a gradual, but large, increase in green vegetation on the planet that has been recorded over the past three decades.

The climate change lobby is concerned about the dangers of global warming. But greening could actually have a bigger effect than warming, Matt Ridley writes in the Australian Spectator. He said he was most surprised by a study done at Boston University in which an ingenious analysis of data from satellites proved greening.

Ranga Myneni, author of the study, demonstrated how large swathes of vegetated areas on earth were getting greener, with only a limited number showing browning.

Myneni’s model postulates that overall in 30 years, the green vegetation on planet Earth has increased by an extraordinary 14 per cent. Moreover this was occurring in all vegetation types — from tropical rainforests to arctic tundra.

Rising carbon dioxide concentrations in the atmosphere is said to be reponsible for the ecological good news in at least half of the greening — rather than, say, the application of agricultural fertiliser, warmer temperatures or increased rainfall.

Carbon dioxide, along with water, are the ingredients that plants use to make carbohydrates, with the help of sunlight. Increasing concentrations of all three should therefore stimulate healthy plant growth.

Myneni’s data is startling, Ridley says. After thousands of experiments in which carbon dioxide levels were augmented to either boost crops or wild ecosystems, the proof is incontrovertible. Commercial greenhouse owners are also aware of the fact and they now routinely maintain carbon dioxide levels in their greenhouses at more than double normal levels, because it makes their tomatoes grow faster.

Ridley, who calls himself a “climate lukewarmer”, says the global effect of CO2 levels on the quantity of vegetation has not been measured as yet. He adds he has been subjected online to withering scorn by the climate spin doctors, who eventually had to admit that he may have been “factually accurate”.

Myneni’s results were published six months ago, and his results are now more convincing than he had concluded in his original lecture.

Myneni maintains that almost three quarters of the cause of greening is carbon dioxide related, up from half. As the paper’s lead author, Zaichun Zhu, of Beijing University, puts it, it’s the equivalent of adding a green continent twice the size of mainland USA.

Back in 1908 Svante Arrhenius, a Nobel laureate and the father of the greenhouse theory, predicted such an outcome. “By the influence of the increasing percentage of carbonic acid in the atmosphere, we may hope to enjoy ages with more equable and better climates,” he wrote. The earth, he predicted, “will bring forth much more abundant crops than at present, for the benefit of rapidly propagating mankind”.

So far, the benefits of global greening have been greater than expected, while the costs of global warming have been smaller than expected and the price of reducing carbon dioxide emissions has been higher than expected.

A new study from New Zealand suggests that at about 425ppm Carbon dioxide, the climate begins to change and doesn’t revert even when Carbon dioxide concentrations go down. This possible threshold will be passed by a large margin, doomsayers maintain.

According to the Desmog environmental website, Lord Ridley’s 8 500-acre family estate, Blagdon, in the UK contains coal mines that have reserves estimated to be worth hundreds of millions of pounds and from which he receives payments.

So the “good news” remain highly controversial. Dr Myneni felt the need to scold Ridley for publicising his research, although he later repeated his claim that “CO2 fertilisation explains 70 per cent of the greening trend”.

As climate economist Professor Richard Tol commented: “The new paper vindicates what Matt Ridley and others have been saying all along — yet they apparently deserve to be kicked nonetheless.”

Republican presidential nominee, Donald Trump has waded into the climate mud-slinging competition by pledging to “stop all payment of US tax dollars to global-warming programs”.

“This is done for the benefit of China because China does not do anything to help climate change,” he added.

In September, President Obama and the Chinese President Xi Jinping formally ratified the international climate-change pact reached last December, in Paris.

It might be a load of hot air, because it pledges to keep the global temperature increase to “well below 2°C,” and “to pursue efforts to limit” the increase to “1.5°C above pre-industrial levels.” If and exactly how China and the US, which together account for forty per cent of the world’s greenhouse-gas emissions, will follow through on their commitments remains to be seen, as the agreement is not legally binding.