How much ocean water?

The gross tonnage of all the world's large cargo ships is about 1 billion tons. Let's wildly overestimate that if you include all the navy ships and small cargo ships you might raise that by an order of magnitude and call it 10 billion tons. A ton of water takes up about a cubic meter, so you get 10 billion cubic meters. The surface area of the oceans is about 360 million square kilometers, or 3.6 x 10^14 square meters. We can find the increase in depth by dividing the volume by the area. That gives something like a 1/30 of a millimeter rise.

Interesting question. A fully loaded super carrier has to displace a considerable amount of water. Add up everything now floating and all of the ships and trash sunk...I suspect there actually may be a slight but measurable rise in ocean levels. Even seabirds resting on the water must displace X amount of water as to fish and sea mammals. A swimming walrus displaces it's above water weight and it's below water bulk displaces an equal amount of water. A herd of those two ton critters is a lot of critter! Could this be quantified and qualified? Any math majors out there?

Global warming is the main culprit. It not only melts glaciers, but it causes the entire ocean to expand as it is heated.

Incidentally the arctic ice is already floating, so melting there has no effect on ocean heights. Antarctic glaciers are mostly on land, so they affect the oceans as they melt.

The weight of water so displaced is exactly equal to the weight of all these floating things combined.

NONE= Global Warming melted a lot of ice and Glaciers and now the oceans are extra high along with a lot of freshwater evaporating into rain clouds and raining most every where. Global warming has been over for more than a year now. An Arabian Opec oil prince has been paying Dubai World $10 Billion a year to pour hundreds of millions of tons of dry land sand into the saltwater making all oceans rise over dry land continents and islands all over earth, but I've been able to stop them with the leaders on earth for 3 years straight, but now who knows who pouring sand to continue making all the oceans rise now. As far as man made products are concerned. What is made does'nt make the water rise, because their either on top of water or underwater. Mike

Insignificant, our oceans cover 70% of the globe