Earth's boundaries on Clubhouse

Description

This group is aimed to discuss only one thing and that is "SAVE PLANET EARTH".

WE CAN'T CROSS THE TIPPING POINTS! But what are tipping points?

The IPCC AR5 (Intergovernmental Panel on Climate Change - 5th Assessment Report) defines a tipping point as an irreversible change in the climate system.

In the context of climate change, an "adaptation tipping point" has been defined as "the threshold value or specific boundary condition where ecological, technical, economic, spatial or socially acceptable limits are exceeded."

What does this mean? Well, essentially once we cross a tipping point of a particular planetary boundary the planet's essential conditions contributing to supporting life moves to a point where there is no coming back and eventually leads to natural catastrophes around the world, the likes of 2020 Australian forest Fire and earthquakes etc etc.

But What are Planetary boundaries of Earth to support morden day life? I mean all forms of life-

THE BIG THREE:

CLIMATE CHANGE - CO2 concentration in the atmosphere must be less than 350 ppm and/or a maximum change of +1 Wm^-2 in Radiative forcing

OCEAN ACIDIFICATION - Average surface seawater saturation state with respect to aragonite (Aragonite is a carbonate mineral, one of the three most common naturally occurring crystal forms of calcium carbonate, CaCO3. It is formed by biological and physical processes, including precipitation from marine and freshwater environments. Aragonite provides the materials necessary for much sea life and also keeps the pH of the water close to its natural level, to prevent the dissolution of biogenic calcium carbonate.) must be greater than or equal to 80% of pre- Industrial Levels.

STRATOSPHERIC OZONE - There must be less than 5% reduction in O3 concentration from preindustrial levels of 290 Dobson units. Basically, this metric ensures that the ozone layer is fine and dandy!

THE SLOW VARIABLES:
BIOGEO-CHEMICAL- Nitrogen (N) Cycle: limits industrial and agricultural fixation of N2 35 TgN yr^-1.
Phosphorus (P) Cycle: Annual P inflow to Oceans not to exceed 10 times the natural background weathering of P.

GLOBAL FRESH WATER USE- Must be less than 4000 cubic kilometres per year of consumptive use of runoff resources.

LAND SYSTEM CHANGE- Must be less than 15% of the ice-free land surface under cropland.

RATE OF BIODIVERSITY LOSS- Mandatory annual rate of less than 10 EXTINCTIONS per million species.
EARTH ALIENS: CHEMICAL POLLUTION & AAL.