80 metres. The following are a series of speculative maps depicting the world under 80 metres (262ft) of sea level rise due to anthropogenic global warming. The figure is drawn from current USGS estimates of how much water would be contributed to sea level by the melting of various ice sheets and thermal expansion, and is the theoretical limit of increase.
To the left is a graph of atmospheric CO2 taken from EPICA antarctic ice cores over the past 800,000 years. When the level slips below around 230ppm (blue) it has indicated a glacial period of advancing ice sheets. The peak during the warm periods has been around 275-300ppm. You can see that in 2019 we were at 412ppm, well above levels ever seen in human history, and with the full effects the increase yet to be seen in the climate.
Currently not even the Intergovernmental Panel on Climate Change’s worst case scenario – RCP 8.5 – is predicting the melting of all ice on Earth. However this may be due to their focus on the near term impacts. A paper in Nature Climate Change (Clark et al. 2016), tried to explore the far future and found that melting and sea levels will continue to increase for at least ten thousand years even if emissions were stopped today. And even if we limited global warming to 2°C, the likely end result will be a sea-level rise of around 25 metres. Another paper, Combustion of available fossil fuel resources sufficient to eliminate the Antarctic Ice Sheet (Winkelmann et al, 2015) modeled what it would take to melt all Antarctic ice and found that a CO2 level of around 4000ppm could nearly do it within 10,000 years and would require the burning of almost all known fossil fuel resources. However, it might not take that much carbon over a longer timescale. Paleoclimate research (McKay et al, 2016) shows that Antarctica was ice free when atmospheric CO2 was last just over 1000ppm, during the Eocene 40 million years ago. So even if the world does not burn all its fossil fuels, over the millennia, the heat trapped by an RCP 8.5 scenario could eventually melt all Antarctica’s ice.
Time is so vast that sooner or later, in the absence of an equally accessible and cheap energy source, I believe humanity or some portion of it will eventually burn all of the planet’s fossil fuels. If not our society, the next one, or the next after that.
I imagine these maps to show the world about 5000-7000 years from now. the seas having risen at a rate consistent with that of the end of the last ice age. A worst case scenario of global warming. The maps do not include any coastal changes due to soil erosion, isostatic rebound, or tectonic shifts which would inevitably occur, they just rely upon current elevation data.
The maps were rendered using United States Geological Survey and Natural Resources Canada Digital Elevation Models (DEM), 7.5′ – 10 metre data to capture the elevations. I also used bathymetry data where i could get it. For Greenland and Antarctica I used data from the NASA National Snow and Ice Data Center. Some of NASA’s blue marble textures were also used as a resource. Except for the greening of the polar regions and a few deserts, I have not dramatically altered the vegetation zones of the future Earth. I would like to update that someday with more research.
I want to add that I am an illustrator not a climate scientist, but have tried to use the data in a careful and thoughtful manner.
The chart below shows average sea level relative to 1900 levels. To the left of present day is a grouping of estimates of the ancient sea level by various researchers. All of recorded human history has occurred in this period. To the right is a graph of an increase of 80 metres by around the year 7000. In reality the seas will rise in fits and starts, interrupted by cooling periods caused by volcanic eruptions and meltwater salinity events, and would also be affected by cycles of solar activity. There are also feedback loops, such of methane released from melting permafrost, which could increase the rate of heating, and whose full effect is only starting to be understood. Currently it is thought that the fastest rates of change will occur in the next 1000 years.
As you might expect, the bay area is catastrophically inundated by 80m of ocean. Also included here is the zoomed out view of the greater bay area. I have not represented any movement of the faults in this map, which if projected over 5000 years, would be as much as several hundred metres.
Given its nature as a river delta, the Vancouver area is incredibly sensitive to sea level rise, and as you can see much of it would be long submerged under 80m.
While not generally thought of being at risk to sea level rise, at 76m above the current sea level, Lake Ontario would eventually be affected.
I decided on a polar projection to this map to emphasize the ice free nature of the pole, and to note the ring of temperate climates in the north.
Morlighem, M. et al. 2017, updated 2018. IceBridge BedMachine Greenland, Version 3. Bedrock elevations. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. doi: https://doi.org/10.5067/2CIX82HUV88Y. May 2020.
The main feature of the south is the reveal of Antarctica without ice. Like the North, I decided on a polar projection to this map to emphasize the ice free nature of the pole, and to note the ring of temperate climates in the south.
In Australia, the massive Lake Eyre is a large below sea level depression that I have filled with water, but is is possible is could be a dry or seasonal basin.
While it is thought it would take thousands of years for entire ice sheet to fully melt, it is interesting to see what lies beneath it. The Amundsen–Scott south pole station is currently 2755m in the air above where the surface pole is on this map. I have added in numerous lakes thinking the land would like muskeg, somewhat like northern Canada, after the melting of the ice.
The map does not account for any isostatic rebound of the surface, which would change the shorelines and lakes significantly. Over 5000 years this could amount to 80-200m of elevation gain in the most depressed regions.
Morlighem, M. 2019. MEaSUREs BedMachine Antarctica, Version 1. Bedrock elevations. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. doi: https://doi.org/10.5067/C2GFER6PTOS4. May 2020.