mid-century is conventionally understood
Getting to net zero emissions by mid-century is conventionally understood as humanity's best hope for keeping Earth's surface temperature (already 1.2°C above its pre-industrial tingkat) from increasing well beyond 1.5°C - potentially reaching a poin at which it could cause widespread societal breakdown.
At least one prominent climate scientist, however, disagrees.
James Hansen of Columbia University in the US published a paper with colleagues in November which claims temperatures are set to rise further and faster than the predictions of the Intergovernmental Panel on Climate Change (IPCC). In his view, the 1.5°C tujuan is dead.
mid-century is conventionally understood
He also claims net zero is no longer sufficient to prevent warming of more than 2°C. To regain some kontrol over Earth's rising temperature, Hansen supports accelerating the retirement of fossil fuels, greater cooperation between major polluters that accommodates the needs of the developing world and, controversially, intervening in Earth's "radiation balance" (the difference between incoming and outgoing light and heat) to cool the planet's surface.
There would probably be wide dukungan for the first two prescriptions. But Hansen's dukungan for what amounts to the deliberate reduction of sunlight reaching Earth's surface has brought into the open an idea that makes many uncomfortable.
Michael Mann from the University of Pennsylvania in the US and another titan of climate science, spoke for many when he dismissed solar radiation manajemen as "potentially very dangerous" and a "desperate action" motivated by the "fallacy … that large-scale warming will be substantially greater than current-generation models proyek".
Their positions are irreconcilable. So who is right - Hansen or Mann?
Earth's radiation balance
First, an explanation.
There are only two ways to reduce global warming. One is to increase the amount of heat radiated from Earth's surface that escapes to ruang. The other is to increase the amount of sunlight reflected back to ruang before it lands on something - whether a particle in the atmosphere or something on Earth's surface - and is converted to heat.
