Tuesday, 5 May 2020

Global Warming

Global warming to push billions outside climate range that has sustained society for 6,000 years

Just like insects, birds and animals, humans have a particular climate niche, scientists have found, with 6,000 years of human history demonstrating how society thrives when we stay within it and the turbulence that ensues when it is pushed out of this zone.

In a stark new finding about the planet’s rapidly warming climate, a study finds that for every 1.8 degrees Fahrenheit (1 degree Celsius) of global average warming, 1 billion people will have to adapt or migrate to stay within climate conditions that are best suited for crop production, livestock and a sustainable outdoor work environment.

They found that people, crops and livestock have heavily concentrated in a narrow band of relatively constrained climate conditions. This range, referred to in the study as the human “climate niche,” has remained largely unchanged since 6,000 years ago.

Projecting into the future using a scenario with high emissions of heat-trapping greenhouse gases, the researchers found that the position of the human climate niche is projected to change more in the next 50 years than it has during the past 6,000. Such a shift would leave 1 billion to 3 billion people outside the climate conditions that have nurtured human society to date.

Global warming fuels algal bloom in Arabian Sea

A study published Monday in the journal Scientific Reports reveals that global warming is fuelling a destructive algal bloom that is disrupting fisheries in the Arabian Sea.

Cold winter monsoon winds blowing from the Himalayas usually cool the Arabian Sea’s surface, which results in the cold waters sinking and being replaced by nutrient-rich waters below. This process, called convective mixing, allows marine algae called phytoplankton, which provides food for a wide range of sea creatures, to flourish from the nutrient-rich waters lit by the sun.

However, melting glaciers over the Himalyan-Tibetan Plateau region have made the winds blowing to the oceans surface warmer and moister, decreasing convective mixing. This change hurts the phytoplankton, but not the Noctiluca because unlike the phytoplankton, it doesn’t need sunlight.

The ability of Noctiluca to flourish amid the shrinking snowcaps has been disrupting marine life in the Arabian Sea since the late 1990s, the study found. Only jellyfish and salps find the Noctiluca edible.



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