Global Change

Loss of coral reefs

Coral reef ecosystems are extremely sensitive to ocean temperatures and pollution. They are extremely diverse ecosystems and support livelihoods of 100s of millions of people. They also protect coastal regions from ravages of ocean-based threats such as tropical cyclones. All coral reefs across the world from the Caribbean to the Great Barrier Reef in Australia are under serious threat and at the risk of disappearing.

Image:  Phys.org 

Mass extinctions

Rapidly increasing temperatures across the world are making condition untenable for all the world's living beings. It is estimated that if the temperatures rise by >4 oC, 40-70% of all species (polar bears to frogs to honeybees) on Earth will go extinct.

Image:  National Geographic 

Melting permafrost

Permafrost (frozen soil and groundwater) in the Arctic regions is melting.  Recently, the town of Verkhoyansk in Russian Siberia hit 100 oF on the first day of summer ! Melting permafrost releases methane gas (more potent greenhouse gas than CO ₂ ) into the atmosphere, causes land to buckle and subside, as well as cause failure of infrastructure (e.g., oil and gas pipelines, power lines, highways, foundations of homes, etc.)

Image:  Wired 

Extreme wildfires

Hotter-than-normal conditions during the summer of 2019 and extremely dry weather in eastern Australia led to extreme wildfires that consumed more than 32,000 sq. mi (about the size of South Carolina), and killed 24 people and more than a billion animals. Such fires are raging in the Amazon basin, the US Southwest, and many other parts of the world. This is expected to be the new normal.

Image:  NY Times 

Poor air quality

Increasing temperatures and population in world's major metropolises (New Delhi, Beijing, Mexico City, etc.) has caused an increase in poor air quality and rise in ground level ozone. These air pollutants have resulted in an increase in poor health for people that live in these cities. In US, many cities in California (e.g., LA and San Francisco) are infamous for their poor air quality. Increase in temperatures is expected to cause more pollution-related deaths around the world.

Image:  NY Times 

Climate refugees

People affected by increasing disasters (e.g., flooding in coastal low-lying areas, persistent droughts and famine, diminishing basic resources, wars over resources) will migrate to areas that are perceived to be safer. Millions of people are expected to migrate in greater numbers in the future.

Image:  CBS News 

More pandemics

The current COVID-19 pandemic was not caused by climate change. However, the changing climate is often a "threat multiplier." As our population increases, we are encroaching deeper into animal habitats. Zoonotic diseases like SARS-CoV-2 are more likely to crossover from animals to humans more easily.

Image:  Washington Post