What changes are likely to happen to the sea level as the greenhouse effect gets worse?

Answer 1

There are three key impacts of sea level rise.

1) INUNDATION (flooding):

Many low lying countries will be under water, including large parts of the USA, UK, Holland, Bangladesh, and many Pacific Island countries.

Note that it is likely that these effects will be delayed, giving the false impression that they are not as serious as might have been feared.

This is because, before the sea level begins to visibly rise, the water level has to equalise globally, that is, the sea water must penetrate and fill every void, hollow and porous body of soil/rock it encounters. Caverns, cave systems, lava tubes, 'cenotes', underground lakes and rivers etc., all must be filled before the waters can rise.

Once this process is complete, however, sea level rise will suddenly gain momentum, as there will be nowhere else for the water to go. that is when we shall see coastal waters rise at vertiginous speed, especially, on a fairly localised scale, during full moon and high tide.

2) UNDERMINING (weakening by fluid penetration of porous rocks and soils):

As water infiltrates soils and minerals it will begin to dissolve some of the matrices that hold together particles in soils and sedimentary rocks, like aggregates, breccias, mudstones, siltstones, sandstones, limestone etc.

As a result of these unevenly distributed weakening of the rock and soils, whole areas of the surface will become unstable, though not necessarily visibly so, as these infiltrations may begin at great depths and progress upwards and outwards, as the sea penetrates deeper inland.

The heavier the construction burden on the rock/soil the more likely the sudden, catastrophic collapse of roads, bridges, cliffs, monuments and any other structure built on undermined land/rock.

2) ECOTOXICOLOGICAL IMPACTS (toxicity in the environment):

There are other hazards likely to stem from the infiltration of sea water into areas that had not been accessible to sea waters for millennia, or even millions of years.

A key one is the dispersion and bio-concentration of pollutants in the ecosystem.

Humanity has been using the land as a waste repository for dead bodies, urban waste, toxic chemicals, radioactive waste, ammunitions etc.

When sea water starts to inundate this class of underground voids it will aggressively begin to dissolve the most water-soluble of them and gradually leach them out into surrounding soils and waters. This is how Persistent organic pollutants and heavy metals, in particular, enter into food chains and "food webs"/"food pyramids".

Where these plumes of toxic liquor flow into bodies of water, four main processes will take over:

A) TRANSPORTATION: currents will transport the toxic effluent out towards the sea

B) ADSORPTION/ABSOPRTION: depending on the nature of the sands, silts and rock strata the toxic liquids encounter

C) ASSIMILATION: aquatic species will breather and ingest toxic liquor

D) BIOMAGNIFICATION: as invertebrates and vertebrates assimilate toxic pollutants in suspension/solution, predators will consume them and accumulate in their tissues.

As higher predators consume them, in turn, the process continues "up" the food chain so that, say 1000 plankton >> 100 crustaceans >> 10 fish >> 1 bird/mammal.

So, if each plankton carries a toxic burden of 0.1mg this is

1st trophic layer 0.1mcg x 1000 plankton = 100mcg

2nd trophic layer 100mcg x 100 crustaceans = 10,000mcg = 100mg

3rd trophic layer 100mg x 10 fish = 1000mg = 1g

So the toxic burden a bird feeding on a dead or dying fish in the above example would assimilate 1g of toxic pollutant for every 10 fish it consumes.

The process continues up the food chain, so that a predator consuming 10 birds would assimilate 10 gr. of toxic pollutant. Note that the LD50[1] for some substances is just a few as low as a few micrograms. Dioxins, for example, have an LD50 of just20 mcg/kg of bodyweight.

Footnotes.

1. The median lethal dose, LD50 (abbreviation for "lethal dose, 50%"), LC50 (lethal concentration, 50%) or LCt50 (lethal concentration and time) of a toxin, radiation, or pathogen is the dose required to kill half the members of a tested population after a specified test duration. LD50 figures are frequently used as a general indicator of a substance's acute toxicity.

Answer 2

As the greenhouse effect increases, the polar ice caps will melt, raising the sea level.

Answer 3

Global warming will melt icecaps and glaciers. This will raise the sea levels.