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Claim 1
‘I think global warming is real, but the effects of climate change are not as bad as was feared. Climate change is real but harmless.’
Rik Leemans, professor of Environmental Systems Analysis: ‘Climate-change deniers currently accept anthropogenic climate change. But then they hasten to add that the warming and its impact will be trivial, many impacts may be positive and adaptation is always feasible. Mitigating greenhouse gas emissions is thus unnecessary.The latest IPCC Climate Change report unambiguously shows that this reasoning is at odds with scientific insights. Compared to IPCC’s 2000 report, which motivated the Paris Agreement’s 2oC climate protection target, the 2014 report shows that we are now much more vulnerable. Ridley is on the academic advisory council of the Global Warming Policy Foundation, which lobbies against climate policy. He cherry-picks arguments from the climate change literature.’
Claim 2
‘The total forest cover in the world has increased by 14 percent in the last 30 years. That greening is 70 percent attributable to the increase in CO2 in the atmosphere.’
Niels Anten, professor of Crop and Weed Ecology: Forest cover has indeed increased in many parts of the world, but it is far from certain that this is mostly due to elevated CO2 levels. Furthermore, the side effects of this greeningare probably not good. Regionally, for instance, itresults in reduced radiation reflection and this contributes to further warming, especially at high latitudes. It probably also speeds up the melting of the permafrost in the artic, adding CO2 emissions on a scale similar to the current emissions of the USA.’
Claim 3
‘Globally, deforestation has almost stopped. In poor countries we are still losing forest, but in rich countries we are gaining new forests. Deforestation in the tropics occurs mainly to meet the firewood needs of the local population.’
Pieter Zuidema, personal professor of Tropical Forests: ‘It is not true that deforestation is mainly a result of the local demand for firewood. Gathering firewood thins the forest but rarely causes deforestation. The main reason for the felling of tropical forests is agriculture. 80 percent of the lost forests are ploughed over for small-scale farming and commercial plantations for palm oil, wood pulp, rubber and soya. To support the idea that deforestation has almost stopped, Ridley uses figures about net forest loss after all the deforestation and the reforestation. But a small net loss does not mean there was not much deforestation. Every year, an area of tropical forest twice the size of the Netherlands disappears, and satellite measurements suggest this has increased recently. The statement that forest cover in wealthy countries is increasing is correct. And to a negligible extent that goes for tropical countries too, but it is too soon for generalized optimism about tropical forests.’
Claim 4
‘In my lifetime the proportion of human beings living in poverty has plummeted from two thirds to less than 10 percent. In line with that, infant mortality has dropped spectacularly on all continents.’
Ruerd Ruben, professor of Impact Assessment for Food Systems: ‘There has indeed been a big drop in the percentage of the world population living in poverty. The World Bank estimated it at 9.2 percent in 2015. But most of that drop is accounted for by China. In Sub-Saharan Africa, 35 percent of the – growing – population is living below the poverty line. And the fall in undernutrition and child mortality has not kept pace with poverty reduction. It is true that child mortality was halved between 1990 and 2015, from 90.6 to 42.5 per 1000, but stunting has only gone down by 30 percent in the same period. So there isn’t a straightforward correspondence between higher incomes and better nutrition.’