The polar ice caps and glaciers around the world contain massive amounts of frozen water. If all this ice were to melt, it would lead to a catastrophic rise in global sea levels, flooding coastlines and low-lying areas. This article will examine the potential impacts if all the land ice on Earth were to melt away.
How much ice is there?
The Antarctic and Greenland ice sheets contain over 99% of the world’s freshwater ice. The Antarctic ice sheet covers an area of around 14 million square kilometers and contains 30 million cubic kilometers of ice. The Greenland ice sheet covers an area of 1.7 million square kilometers and contains 2.6 million cubic kilometers of ice. If just these two ice sheets were to melt completely, global sea levels would rise by around 70 meters.
Additionally, there are over 198,000 glaciers worldwide excluding the polar ice sheets. These glaciers cover an area of over 730,000 square kilometers and contain roughly 158,000 cubic kilometers of water. If all the glaciers were to melt, this would contribute about 0.5 meters to global sea level rise.
In total, if all the land ice on Earth were to melt, global sea levels would rise by approximately 70.5 meters. This is a catastrophic amount given that the average depth of the oceans is about 3.7 kilometers.
What areas would be impacted?
A sea level rise of 70 meters would dramatically reshape coastlines around the world. Here are some of the major impacts:
- Much of Florida, Louisiana, the Netherlands, Bangladesh and other low-lying coastal areas would be completely submerged.
- Major cities like New York, London, Shanghai, Sydney, and Tokyo would be partially or fully flooded.
- Large parts of countries like Denmark, Belgium, Vietnam, and Thailand would be underwater.
- Small island nations like the Maldives, Seychelles, and Tuvalu would likely disappear entirely.
- Major rivers like the Hudson and Thames would swell to over 100 km wide at their mouths.
- Global coastlines would recede inland by hundreds of kilometers in some places.
Essentially, all coastal areas and island nations would be severely impacted or lost entirely. Even higher elevations well inland would see impacts.
How would it impact populations?
According to some estimates, over 680 million people live in areas that would be submerged or regularly flooded by a 70 meter sea level rise. This is close to 10% of the current world population.
Some of the most densely populated urban areas would be partially or fully underwater, displacing tens of millions of people. Shanghai, Mumbai, New York, Tokyo and other major cities would likely need to be abandoned entirely.
Additionally, the loss of major river deltas like the Nile and Ganges would severely disrupt local agriculture that supports large populations. The loss of the Mekong delta could impact the food supply for over 20 million people alone.
The migration of hundreds of millions of displaced coastal residents inland would stress resources and potentially cause humanitarian crises, unrest, and conflict. Low-lying island nations may need to be completely evacuated or abandoned.
Overall, the impacts on global populations from housing and infrastructure loss, food security threats, and mass migration would be catastrophic.
What would the economic impacts be?
The economic impacts of losing the major coastal cities and agricultural areas would be severe:
- Over $1 trillion worth of infrastructure and real estate would be lost in coastal cities like New York and Shanghai.
- Loss of major port facilities would severely disrupt global trade and supply chains.
- Loss of highly productive agricultural deltas and estuaries could impact global food supplies and prices.
- Flooding of coastal oil and gas infrastructure would disrupt global energy supplies.
- Mass migration and loss of economic centers would disrupt markets and may trigger global financial crises.
- Hundreds of trillions of dollars would likely be lost from the submersion of coastal megacities.
Adapting to these disruptions would require relocating industries, agriculture, and trade networks further inland. The costs for flood defenses, relocations, and rebuilding would likely run into the tens of trillions of dollars globally.
How would ecosystems be affected?
The flooding of major coastal areas and river deltas would have devastating ecological impacts:
- Coastal wetlands, mangrove forests, and estuaries that support high biodiversity would disappear.
- Saltwater would intrude hundreds of kilometers up major rivers, altering their biological communities.
- Flooding could eradicate habitats like the Florida Everglades and Amazon basin.
- Shorelines would migrate inland over existing forests, plains and deserts.
- Coral reefs and marine ecosystems would be severely disrupted by rapid sea level rise.
- Extinction rates may accelerate, particularly in isolated environments like islands.
While some ecosystems and species would shift inland with the encroaching coastlines, many natural environments unique to current sea levels would be lost. The rate of sea level rise would likely outpace the ability of many ecosystems to adjust, resulting in widespread habitat loss and species extinctions.
Conclusion
In conclusion, if all the world’s ice were to catastrophically melt, the impacts on human civilization and natural ecosystems would be severe. With over 70 meters of sea level rise, all coastal areas and low-lying plains would be submerged, displacing hundreds of millions of people and trillions in infrastructure and economic activity. While an abrupt melting of all ice on Earth is unlikely in the near-term, ongoing melting of glaciers and polar ice driven by climate change will result in major changes to coastlines and populations on a smaller but still highly consequential scale. Preventing the accelerated loss of land ice needs to be a top priority to avoid potentially disastrous impacts to societies and ecosystems across the globe.