The World Bank issued a frightening report in 2018 that 147 million people who live in coastal zones on the world’s continents are threatened with inundation from sea level rise caused by climate change. But new findings released this month by scientists at Nature Communications reveal that the World Bank study grossly underestimated the threat of sea level rise because it relied on old, inaccurate technology that overestimated the height of coastal elevations in countries around the world by 6 feet or higher. This brings hundreds of millions more, almost 10% of the world’s population of 7.8 billion, to exposure from the risks of rising seas and storm surge. A six-foot-height difference, in this case an erroneous over estimation of land elevations in coastal communities, can often mean the difference between devastating flooding of cities and farms or living on safe high ground.

Based on the new technology that found many coastal zones to be much lower than previously thought, by 2050, rising oceans will completely flood the land where 300 million of the world’s coastal population lives. By 2100 an additional 200 million people will be flooded.

Sea level rise is from two causes. The first is global warming that causes ocean water to heat and expand its volume. Ninety percent of the human caused excess heat in the atmosphere is absorbed by the world’s oceans. The atmosphere would be 93 degrees warmer, a hellish, uninhabitable planet, if the oceans did not absorb this excess heat. The second cause of rising sea levels is from melting of the great ice sheets on the Himalayas, the Rockies, Greenland and Antarctica. The continents of Greenland and Antarctica hold the largest amount of fresh water on the planet in their massive, frozen ice sheets. 

If Antarctica and Greenland become more unstable and melt at a faster rate, then by the year 2050, a population of between 270 to 340 million who live in coastal zones of the world will experience dangerous, intermittent annual flooding events. By the end of the century between 380 and 630 million people will see intermittent annual flooding.

Sea levels have increased an average of 7 inches since the Industrial Revolution. Most of that increase took place after 1980. With an additional sea level rise of just 3 feet, two million Americans will see their homes permanently flooded. If sea levels rise an additional 6 to 8 feet, there will be 6 million Americans who will lose their homes. That is a likely outcome by the end of the century if we continue business as usual and the emissions levels continue to increase at the present rate of 1% or 2% each year.

When salt water encroaches on coastal land it contaminates fresh water underground aquifers that supply drinking water and provide irrigation for farms. Coastal infrastructure, electric generating plants, roads, bridges, airports, schools, hospitals and government facilities are all threatened by coastal flooding. It’s not just a one-time flooding event that washes away a coastal population. It’s a gradual series of inundations that incrementally degrade and compromise an area. Many coastal zones will become uninhabitable before they disappear under rising oceans.

The Northeast US will experience a much higher sea level rise by 2100 than most other coastal areas of the globe. The next highest flooding levels in the US will take place in the mid-Atlantic and the low-lying Gulf coast states of Louisiana, Mississippi, Alabama and Florida.

California and the Pacific Northwest. will not be exempt to flooding, it will occur in those regions. but at a slower rate.

Very large populations in low-lying deltas in Asia and India will experience devastating coastal flooding by 2050 including 42 million who live in Bangladesh, 36 million in India, 31 million in Vietnam, 23 million in Indonesia and 12 million in Thailand.  Bombay, with a population of 20 million is expected to be under water by 2050 including its two nuclear generating plants.

During 2018 there were 60 million people throughout the world who were displaced by severe weather related events. In the coming decades, as sea levels rise and hundreds of millions are displaced within their own home country or look to migrate to other countries, a humanitarian crisis the likes of which the world has never witnessed, will occur. Many urban areas in the world will have to prepare for a large influx of climate refugees who will need costly assistance for housing, health care, social services, education and job training.

Local coastal economies that are dependent on large population densities will disappear. Supply chains of materials, food and essential products will be disrupted in coastal zones and affect populations throughout the world, including rich countries, who depend on those goods.

The wealthy, developed countries are responsible for almost all of human caused climate change from the accumulated emissions of fossil fuels during the last 150 years. The US with only 4% of the world’s population has contributed 25% of the accumulated carbon in the atmosphere as a result of its industrialization. Carbon emissions persist for thousands of years in the atmosphere. The US also contributes 15% of annual global emissions.

Instead of converting to renewable energy sources, will the global north and Australia continue very high per-capita fossil fuel emissions levels to maintain their high standard of living? Can we expect the wealthier countries to recognize their liability as the main contributors to the climate crisis and extend technical and financial help to the poorer countries to help them adapt to climate change? In coming decades, will the industrialized nations welcome the hundreds of millions of climate refugees from other countries whose plight they have mainly caused? 

There must be a 45% reduction of the world’s greenhouse gas emissions by 2030 and net neutral emissions by 2050 to avoid the worst impacts of climate change including rising oceans. To. achieve this  sharp reduction, the nations of world cannot continue to build coal-fired electric generating plants that are proliferating across India and Southeast Asia. The US and other developed countries must stop converting coal-fired plants to ones fueled by natural gas – which is not a bridge to clean energy but a very potent fossil fuel that is a major contributor to the level of carbon in the atmosphere.

The technology already exists for renewable energy to generate 100% of our power needs, especially wind and solar. What is lacking is the vision and political will to make it happen. Without instituting fundamental changes to our economy, that are based on renewables, both rich and poor countries alike will suffer unimaginable devastation and hardship from sea level rise caused by climate change.

_{Instead of converting to renewable energy sources, will the global north and Australia continue very high per-capita fossil fuel emissions levels to maintain their high standard of living?   Can we expect the wealthy countries to recognize their liability as the main contributors to the climate crisis and extend technical and financial help to the poorer countries to help them adapt to climate change?   In coming decades, will the industrialized nations welcome the hundreds of millions of climate refugees from other countries whose plight they have mainly ca}