Israeli Scientists Find the World Needs Both New Forests and Solar Farms to Fight Climate Change

Left: Yatir Forest located in the northern region of the Negev Desert – the largest of the forests planted in Israel by the Jewish National Fund. Right: The solar farm in the Arava where the measurements were conducted. Photos: Jonathan D. Muller Weizmann Institute

A new Weizmann Institute study shows that building solar farms in arid regions is a far more effective way to tackle the climate crisis than planting forests. So, instead of just adding new green areas the world should focus on also increasing the use of solar energy.

The new study may have found the most effective use of a certain plot of land in terms of the climate crisis, whether it is planting a forest, which is a natural means of absorbing carbon dioxide from the atmosphere, or erecting fields of solar panels, which reduce the emission of carbon dioxide into the atmosphere.

It was led by Dr. Rafael Stern, Dr. Jonathan Muller and Dr. Eyal Rotenberg from Prof. Dan Yakir’s lab at the Earth and Planetary Sciences Department of the Weizmann Institute of Science and was based on findings from arid areas and on comprehensive measurements of the energy flow exchanged between the ground and the atmosphere.

But both the green, natural forest and the artificial, dark “solar forest” produce other effects, some of which can be problematic from a climate perspective, said the researchers. They are both relatively dark, which means that they absorb a large proportion of the radiation from the Sun (making them “low albedo” surfaces in the professional jargon) and, as a result, they heat up. Some of this energy is used for photosynthesis in natural forests or to produce electricity in solar “forests” – but most returns to the atmosphere as fluxes of energy, heating it up. In contrast, the light-colored desert soil, for example, reflects a significant portion of the sunlight back into space, which does not add to the accumulated heat in the atmosphere. (Such soil is known as a surface with a “high albedo.”)

Stern and Muller said, “Our study unequivocally shows that in arid environments, where most of the open land reserves exist, building solar farms is far more effective than planting forests when it comes to dealing with the climate crisis. In this environment, erecting solar panels on areas that are far smaller than forests (up to one hundredth of the size) will offset exactly the same quantity of carbon emissions. Having said that, forests currently absorb close to one-third of humanity’s annual carbon emissions, so it’s of paramount importance to safeguard this capability and prevent the kind of widescale deforestation that takes place in tropical regions.”

Moreover, they explained, forests play a vital role in the global rain cycle, in maintaining biodiversity and in many other environmental and social contexts. Therefore, the conclusion from their study, they assert, mean that the world must protect the Earth’s forests, and that the most appropriate solution to the climate crisis is to “combine the planting and rehabilitation of forests in humid regions with erecting fields of solar panels in arid regions.”