When will the seas rise to 7m, 13m, and 60m?

answering question fraught difficulties, not least because don’t know how fast sea-levels going change in future.

first need consider whey sea-levels rising @ all. there 2 main factors , 1 melting of polar ice , second thermal expansion of seas , oceans (other factors small enough inconsequential).

know how fast polar ice melting @ moment – it’s little on half trillion tonnes per year. can estimate how fast melt in future based on series of scenarios. these same scenarios determine how oceans warm , therefore how expand.

problem further go future more fuzzy these scenarios become. we’re fine projecting few years ahead because change 1 year next small. time extend more few decades future effects of slight changes becomes magnified , there’s large range of possible outcomes.

however, type of sea-level rises you’re referring can ever happen on timescales of centuries , millennia.

worst-case scenario presented gravity recovery , climate experiment (grace) data projects sea-level rise of 1400mm in next 100 years. scenario around 600mm.

based on worst-case scenario 300 350 years before sea-levels rose 7 metres. however, wouldn’t happen because in 100 years fossil fuels going run out , means primary source of greenhouse gas emissions gone.

rather seeing continually increasing rise in temperatures , sea-levels, see rapid rise perhaps next 100 years or levelling off. take in order of 10 20,000 years state of equilibrium reached in no further ice-melt , sea-level rise occurred.

if nobody did slow down effects of climate change , witnessed worse-case scenario we’d see 7m rise in sea-levels in 500 years. 13 metre rise take lot longer – several thousand years. effect 60 metre rise in sea-levels require significant amount of polar ice melt, coupled prolonged , pronounced heating of oceans, we’d looking @ somewhere in order of 20,000 years.

maths involved in making accurate calculations exceptionally long-winded. can tell previous calculations if temperature rise 7°c on next 500 years , remain indefinitely @ elevated temperature greenlandic ice melt after 8,000 years , antarctic ice after 128,500 years. mean in 8,000 years time sea-levels 14 metres higher @ present , time antarctica had melted 140 150 metres higher.

however, on these time scales have influence of orbital variations take consideration , means hypothetical 7°c rise in temperatures cancelled out eccentricity of earth’s orbital path around sun… in short, it’s not going happen.

important thing remember sea-level rise going slow process. it’s on next 100 years we’ll see 600mm rise, works out average of 6mm year. @ rate have plenty of time prepare.

what rough prediction dates each of those?

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