How Big Would Noah's Ark Need to Be to Save All Life on Earth?

Could Noah's Ark, as described in the Bible, actually house enough animals to repopulate the Earth after a global flood? Let's dive into the science and logistics of such an undertaking.

The Biblical Blueprint

According to the Bible, God instructed Noah to build an ark of cypress wood, coated with pitch, with specific dimensions: 300 cubits long, 50 cubits wide, and 30 cubits high. A cubit, an ancient unit of measurement, varies between 17.9 to 20.6 inches (45.5 to 52.3 centimeters).

Ark Replicas

Several Noah's Ark replicas have been built, with varying dimensions:

One measures 135 meters long, 30 meters wide, and 23 meters high.
Another comes in at 155 meters long, 26 meters wide, and 15 meters high.

For comparison, the Titanic was 269 meters long, 28 meters wide, and about 31 meters deep.

Could It Float?

A study at the University of Leicester found that an ark built to biblical dimensions, using a cubit of 48.2 centimeters (1.58 feet), would measure 144.6 meters long, 24.1 meters wide, and 14.46 meters tall. Such a vessel, made of cypress wood, would weigh approximately 1.2 million kilograms (2.65 million pounds) and float in seawater, dipping only about 0.34 meters (1.1 feet) into the water.

Structural Challenges

However, simply floating isn't enough. The ark would need to withstand a global flood. A wooden vessel of this size would face significant structural issues at sea. Smaller boats easily navigate waves, but an ark the size of Noah's would experience immense strain, leading to sagging and hogging, potentially causing structural failure.

The Limits of Wood

Wood, while strong and light, has limitations. Without modern glues and steel plates, joining beams to create a super beam strong enough to support the hull is impossible. The largest wooden ship ever constructed, the Wyoming (1909), was only two-thirds the size of Noah’s Ark. Even then, it flexed and twisted in heavy seas, causing leaks and eventually sinking in 1924.

A Flotilla Solution?

One suggestion is that Noah could have built a flotilla of smaller boats, attached with ropes and gangplanks. This would allow the fleet to move with the waves, rather than resisting them.

Cargo Capacity

Assuming calm waters, what cargo capacity would the ark have? According to Archimedes' principle, the buoyancy force equals the weight of the water displaced. The University of Leicester study estimated the ark could support 50.54 x 10^6 kg (around 55,000 US tons) of cargo.

How Many Animals?

Taking the humble sheep as the 'average' animal mass (23.47kg or 51.74 pounds), the ark could theoretically support 2.15 million sheep. However, space is also a factor. UK guidance suggests a sheep needs about 1.2 square meters (12.9 square feet) of space, or 1.33 cubic meters (46.97 cubic feet) to live comfortably. The ark's capacity of 50,391 cubic meters could house 37,887 sheep living comfortably or 148,209 sheep crammed in transport style.

The Number of Species

The Bible instructs Noah to take "seven pairs of every kind of clean animal… and one pair of every kind of unclean animal.” The term "kind" is open to interpretation, ranging from species to family level in scientific taxonomy.

Biblical scholars estimate Noah needed to take between 2,000 and 50,000 individual animals. However, to save all species on Earth today, the numbers are far greater.

Saving All Species

Estimates suggest there are approximately 8.7 million species on Earth, with 1.25 million identified and classified. Of those, about 950,000 are animals, and 75% live on land. This means finding space for 712,500 different species.

Minimum Viable Population

Taking two of each species would lead to severe inbreeding. The minimum viable population (MVP) is the lowest number a biological group can fall to before facing serious extinction risks. While MVPs vary, the '50/500' rule suggests 50 individuals to prevent inbreeding and 500 to maintain genetic diversity. Using 500 individuals per species, the ark would need to carry 356.3 million animals.

Space Requirements Revisited

Considering that only 3-5% of animals are vertebrates (sheep-sized), the ark would need 4,845,000 cubic meters to house them. Factoring in invertebrates, even assuming the size of a common pavement ant, the Debunked Ark would need approximately 5,000,000 cubic meters (176,573,334 cubic feet).

The Verdict

Noah's Ark, as described, is too small to save all life on Earth. A fleet of 100 Noah's Arks or a larger flotilla of smaller wooden arks would be necessary.

A Modern Equivalent?

The Seawise Giant, constructed in 1979, was 458 meters long, 30 meters deep, and 69 meters wide, with a capacity of 937,000 cubic meters. However, even five of these would be needed to match the capacity of the ark needed to save all species.

The Food Factor

Noah's Ark was afloat for 150 days. A sheep consumes 150kg of grass over that period, while an ant consumes only 0.0015kg. This translates to 3420 kg of food for invertebrates and a staggering 51.3 billion kg for vertebrates.

The world's largest container vessel can carry around 232 million kgs of cargo. This means that even with the largest container vessel, it would be impossible to carry enough food for all the animals for 150 days.

Conclusion

While the story of Noah's Ark is a powerful tale, the logistics of saving all life on Earth on a single vessel are scientifically implausible. The ark would need to be significantly larger, structurally sounder, and capable of carrying vast amounts of food to sustain its inhabitants.