Under the most extreme climate change scenarios sea levels could rise by as much as 4-6 m by 2100. When sea level rises by, let say 5 m, that means anything less than 5 m above sea level at the moment will be underwater. The first place to become completely submerged will be the country with the lowest maximum elevation above sea level. That happens to be the Maldives, which has maximum elevation of only 1.8 m! That could be submerged by even low to intermediate climate scenarios.

Luckily for Tasmania, it has lots of mountains, meaning most of the state well above sea level. The high point in Tasmania (mt. Ossa) is 1,617 m above sea level. Even the most extreme sea level rise projection don’t come close to reaching that, so there is a near 0% chance Tasmania becomes completely submerged. Although towns, homes, and ecosystems on the coast, near the beach, could definitely run into trouble!

Climate can impact Tasmania sea horses in many ways. To understand the total impact, we need to think about not only what warmer water will do to the seahorses themselves, but also the things the eat and the things that eat them! We are not exactly sure how this will play out, but one thing is for sure: For reef-dwelling animals that enjoy colder water for any number of reasons, there is not much space to move furth south in Tasmania before hitting the inhospitable Southern Ocean.

Specifically, we have seen a nearly 60% drop from in the population of the Weedy Seadragon in Southern Tasmania. However, it is important that this could be caused by other human impacts like poaching. And some evidence does suggest sea horses will be able to adapt to warmer waters as they already live in quite a large range of temperature conditions.

There definitely could be. Marine plants, like land plants, need light for photosynthesis. But unlike on land, light can only penetrate into the surface of the ocean, about 100m deep. Now, marine plants, known as phytoplankton, live in the surface ocean where there is light. However, when the ocean gets cold is gets denser. That dense (heavier) water the sinks mixing phytoplankton down deeper into the ocean, sometimes so deep there isn’t any light.

In a warming climate the ocean won’t get as cold, and in turn might not mix as deep. This would give phytoplankton access to more light and could allow them to be more productive and therefore provide more food for marine animals as well.

However, there are many other factors at play. For example, phytoplankton also need nutrients which are mor common at depth, so less mixing could mean less nutrients. Their predators (zooplankton) also may be able to eat them faster in a warmer ocean. So, the net effect of climate change on marine plants is still unknown. As for the animals, more plant productivity could be a good thing, but even that would come with major shifts in the timing in location of when and where the plants grow, which could create a major ecological problem.

On average, the global sea level is expected to rise by about 40 cm, nearly half a meter, by 2050. Of course, sea level rise depends on how much carbon dioxide emissions are released by humans. However, in 2050 there actually isn’t much difference between predictions of the best (RCP2.6) and worst (RCP8.5) case scenarios. It is not until after 2050 that their paths really diverge. That’s because it takes a lot longer for the ocean and ice on the planet to respond than the atmosphere.  

Interestingly, the amount sea level rise will be quite different depending on where you are.  In Sydney, for example we might expect .2 m by 2050, but in NYC it could be up to .45. This is because there is a lot more land in the northern hemisphere and all that land is very heavy. Its weight actually pulls water to the north via the force of gravity. 

To calculate how much land that increase in sea level will flood, you also need to consider how far above sea level the coast line is. Over all, once you consider the shape the coastline around the world, we could be looking at 4.3 million acres underwater. That land contains the homes of 40-150 million people. 

Everyone takes a different path, but the best way is to keep asking questions; at school, at home everywhere! Questions are really the core of science, and as the saying goes, there really aren’t bad one.  Asking questions opens doors, makes you meet new people, and leads you down paths you never expected to go down.  They don’t even have to be questions about science, per se. It can just be asking how you can get involved. 

For me, I started as an engineer in Uni and didn’t really know what I want to do after I graduated.  Then one day I asked a professor if there was any research he was doing that I could help with. Lo and behold, he said yes, and now here I am 12 years later, a real life oceanographer and climate scientist.  So just remember, it never hurts to ask!