2020–the Earth is about to experience a “mini ice age” says NASA, with the Sun entering a “grand solar minimum”–its lowest state of activity in over 400 years. As the Sun becomes more dormant and global temperatures are said to decrease by around one degree celsius, scientists are predicting some food shortages and extra-cold winters. But the theory is under debate.

“The Sun is a seething mass of activity–until it’s not. Every 11 years or so, sun spots fade away, bringing a period of relative calm. This is called solar minimum,” says Dean Pesnell at Goddard Space Flight Centre.

Sunspots have been under telescopic observation since Galileo’s times in the 1600’s.

“It appears that after the course of a certain number of years, the appearance of the Sun repeats itself in respect of the number and size of the spots,” wrote Christian Horrebow in 1775.

The Sun–a massive nuclear fusion reactor a million times larger than our Earth–is responsible for the abundance of energy reaching our planet. A change in the distribution of energy that reaches us is known to dramatically change the temperatures we experience.

“However, since 1970 global temperatures have shot up by almost 0.7 C, while the amount of solar energy reaching the Earth has actually declined. Similarly, the upper atmosphere is cooling while the lower atmosphere warms, a clear fingerprint of warming from greenhouse gasses rather than the sun,” said Miller et al in 2012.

Climate is undoubtedly a complicated picture that involves many aspects.

The most commonly agreed hypothesis about the “Little Ice Age”– a period between about 1300 and 1870 which saw much colder winters than during the 20th century–is that it was caused by increased volcanic activity.

Georg Feuner and Stefan Rahmstorf estimated back in 2010 that, based on NASA’s observed temperatures over the last two decades, global temperatures will only be lowered by 0.3 degrees celsius despite the grand solar minimum, due to counteracting effects by global warming.

There is certainly growing concern and uncertainty about our Earth’s weather patterns with increasing unpredictability in recent times, including major cold spells; record heat waves; devastating bushfires from California, to Australia, and all the way up into the Arctic circle; droughts; flooding and failed crops. And the large majority of climate experts blame greenhouse gasses like CO2.

But one man from the Institute for Advanced Study in Princeton, New Jersey–the same building that Einstein worked in and where some rather extraordinary thinking happens–has a contrarian view.

“The whole Earth is growing greener as a result of carbon dioxide in the atmosphere,” says 96 year old theoretical physicist and mathematician, Freeman Dyson.

“It’s increasing all kinds of growth in the biological world and that’s more important and more certain than the effects on the climate,” he adds.

Mr Dyson, who began researching the effect of CO2 on vegetation 37 years ago, says the amount of carbon dioxide in the atmosphere has gone up about 40 percent in the last 130 years of measurement. About 50 percent of that CO2 has gone into raising vegetation–which has been observed to have had a 20 percent increase.

“I don’t want to analyse other people’s motives,” says Dyson.

“There certainly is an enormous religion in which there are lots of true believers, who think that climate change is evil and that we’re going to run into big catastrophes if we don’t do something drastic. That’s a sort of belief system that exists; I don’t understand it and I don’t pretend to understand their motives.”

Manabe Shukurō, a Japanese meteorologist and climatologist, says that although most global warming theories are based on results from climate modelling tools, those machines, although excellent for understanding climate, are very bad tools for actually predicting climate into the future. Since the models only take into consideration a few of life’s factors, a lot is left out of the picture, in a real world where many issues are complicated.

“You can’t model everything. It’s way, way out of sight,” agrees Dyson.

Scientists believe that sunspots and the Sun’s magnetic cycle certainly does change, although its temperature does not change.

Astrophysicist Nir Shaviv says that the Sun’s activity cycle does have a direct effect on the Earth’s climate and has to do with the cosmic rays and radiation that makes its way into our planet’s atmosphere.

So while experts seem to agree that the Sun and CO2 levels do play a role, they are hugely divided about the overall picture that we are seeing.

“Man Made climate change certainly is real. There’s no doubt it’s real; the question is, ‘how much?’ and whether it’s good or bad. Those are quite separate questions,” says Dyson, who grew up in the 1930’s and who says he can only be optimistic about the future.