"Every other ocean in the world has been damaged or modified by human activity," Young said.
"But the Ross Sea, because of its isolation and because its protected by ice, remains absolutely pristine."
Deep in the Southern Ocean, between Antarctica's Victoria Land and Marie Byrd Land, the Ross Sea is covered with ice for most of the year.
"Even though it's one of the most extreme environments on Earth, life actually hangs in a delicate balance."
Commercial fishing had threatened to destroy this precious equilibrium.
2. It's a biodiversity hotspot
"The Ross Sea teems with wildlife and there's many species there that you won't find anywhere else on the planet."
At least ten mammal species, six bird species and 95 fish species are found there, as well as many invertebrates.
"I call it the Serengeti of the south."
Some of its notable residents included emperor and adelie penguins, Antarctic and snow petrels, south polar skua, Weddell and crabeater seals, Antarctic minke whales, orcas, leopard seals, Antarctic krill, Antarctic silverfish, and, of course, Antarctic toothfish.
"We are losing biodiversity around the planet at a huge rate of knots and we just have to protect these last untouched areas, because this is what makes Earth special, it's what makes it interesting.
"We are inter-connected - humans are a very small part of the picture - and it's actually getting critical."
3. It's a living laboratory
"Scientists refer to it as one of the last living laboratories, because it's a place that can teach us about the workings of all marine ecosystems," he said.
"The balance you find in the Ross Sea, with all of its top predators still intact, is very different from a modified marine ecosystem.
"Everywhere where humans have been, where we've taken out the top predators, you get a foodweb that's in the shape of a pyramid.
"But [ecologist Dr] Dave Ainley describes the Ross Sea as more like a column - scientists don't understand why, they just know that it is, and that's how oceans used to be."
The Ross Sea was also incredibly important for studying what was happening to the world's climate system.
Antarctica itself is often likened to the fly wheel of the global climate system, as the planet's oceans and atmosphere spins around it, transporting heat around the globe.
The frozen continent and its cold water masses thus determine much of what happens in the rest of the world's oceans, climate and biodiversity.
"The Southern Ocean affects all of the oceans, and it's the oceans that connect all of us; without life in the ocean, there is no life, full stop."
4. This agreement offers a ray of hope for humanity.
"With so much conflict and tension around today, the fact that 25 nations have sat around a table and collectively agreed to protect this very special place is something which should be celebrated."
In 2012, the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) came close to signing off on a 2.27 million sq km reserve proposed by New Zealand and the US - 1.6 million sq km designated no-take zone - but all 25 nations were unable to agree by the summit's 11th and final day in Hobart.
The impasse was a crushing disappointment for environmental groups, scientists and the many diplomats who had worked hard to get the deal over the line.
For Young, however, witnessing first-hand the level of bureaucracy involved in CCAMLR had been a reality check.
"It was a big revelation for me, and I thought, oh my God, how on Earth can we protect the Ross Sea?
"It's actually gone through quite quickly when you look at all of the different cultures, nations and agendas that were around the table; I'd expected it to take a really long time."
That CCAMLR had now delivered a marine reserve - although smaller at 1.55 million sq km with 1.2 million sq km of it a designated no-take zone - was a triumph to be hailed, he said.
"It's a victory for common sense and it offers a ray of hope for humanity," he said.
"I also think it's a real credit to New Zealand and to the US for keeping this MPA at the top of CCAMLR's agenda."
5. It's a gift for future generations.
Young saw the Ross Sea decision as meaningful as the Antarctic Treaty signed in 1959.
"We have benefited from the generosity and insight of those nations that 50 years ago preserved Antarctica for peace and science, and now it's great to be giving future generations a gift like the Ross Sea.
"Even if many people don't get to go to the Ross Sea - and many won't - it's still really good to know that those places exist."