When the world has got hold of a lie, it is astonishing how hard it is to kill it. You beat it over the head, till it seems to have given up the ghost, and behold! the next day it is as healthy as ever. –Edward Bulwer-Lytton

The blurb for the Canadian version of a National Geographic program (as it refers to Celsius, not Fahrenheit) recently screened here, although it was actually made in 2007, reads like this:

As the volume of greenhouse gases increases yearly, scientists [which scientists? — Eds] are warning that the global average temperature could increase by as much as 6 degrees Celsius over the next century, which would cause our world to change radically. This documentary joins British author Mark Lynas and climate experts as they take a look at what effect each rise of 1ºC could have on the world.

Even if greenhouse emissions stopped overnight, the concentrations already in the atmosphere would still mean a global rise of between 0.5 and 1ºC. But what if the global temperature increased by another degree? According to Mark Lynas, author of Six Degrees, the changes would no longer be gradual. Greenland’s glaciers and some of the lower lying islands would start to disappear. At 3ºC higher the Arctic would be ice-free all summer, the Amazon rainforest would begin to dry out and extreme weather patterns would become the norm. An increase of 4ºC would see the oceans rise drastically [our emphasis – Eds]. Then comes the twilight zone of climate change, if the global temperature rises again by another degree. Part of once temperate regions could become uninhabitable, while humans fight each other for the world’s remaining resources. The sixth degree is what is called the doomsday scenario as oceans become marine wastelands, deserts expand and catastrophic events become more common.

If it sounds very much like what Al Gore came up with in his discredited An Inconvenient Truth made the year before, then it probably had the same motivation — to make a fast buck.

The History Channel has decided to do one better and claims in this program that two degrees Celsius is the magic tipping point.

But there is at least some critical analysis of these outlandish claims, even if it doesn’t get nearly as much popular coverage: an article from 2009 in the Daily Telegraph headed Rise of sea levels is ‘the greatest lie ever told’ begins:

If one thing more than any other is used to justify proposals that the world must spend tens of trillions of dollars on combating global warming, it is the belief that we face a disastrous rise in sea levels. The Antarctic and Greenland ice caps will melt, we are told, warming oceans will expand, and the result will be catastrophe.
Although the UN’s Intergovernmental Panel on Climate Change (IPCC) only predicts a sea level rise of 59 cm (17 inches) by 2100, Al Gore in his Oscar-winning film An Inconvenient Truth went much further, talking of 20 feet, and showing computer graphics of cities such as Shanghai and San Francisco half under water. We all know the graphic showing central London in similar plight. As for tiny island nations such as the Maldives and Tuvalu, as Prince Charles likes to tell us and the Archbishop of Canterbury was again parroting last week, they are due to vanish.

But if there is one scientist who knows more about sea levels than anyone else in the world it is the Swedish geologist and physicist Nils-Axel Mörner, formerly chairman of the INQUA International Commission on Sea Level Change. And the uncompromising verdict of Dr Mörner, who for 35 years has been using every known scientific method to study sea levels all over the globe, is that all this talk about the sea rising is nothing but a colossal scare story.

The problem is that quite a few people in high places have been taken in by it, including former KCDC boss Dougherty who seemed to think that a huge chunk of Kapiti’s coast was going to be submerged, declared that there was now a doctrine of ‘managed retreat’ and told candidates in the 2013 elections not to dispute this (he said nothing in 2016, but still refused to remove his map hazard lines).

This Cameron Slater article from June last year, which also examined the issue with graphs on the experience of Nauru and the Solomon Islands, likewise countered the Dougherty notion… “there are huge areas of the globe where there is simply no recorded movement, either up or down in the level of the sea.”

Well, that isn’t really too surprising from even a cursory glance at basic facts:

According to the US Geological Survey:

97.2% of all water on Earth is in the oceans and inland seas
2.1% is frozen in glaciers
0.6% is in groundwater and soil moisture
less than 1% is in the atmosphere
less than 1% is in lakes and rivers
less than 1% is in all living plants and animals.

According to NASA:

Estimate of Global Water Distribution

Volume (1000 km³) / Percent of Total Water
Oceans, Seas, and Bays: 1,338,000 / 96.5
Ice Caps, Glaciers, and Permanent Snow: 24,064 / 1.74
Groundwater: 23,400 / 1.7

There is a little variation in these figures, but they’re fairly close. Assuming that ‘ice caps’ means both polar ice caps, then because it’s sea ice, if it all melted, the Northern Polar Ice Cap would make no difference to sea level as ice is 9% less dense than liquid water and that 9% goes on top of the water as enormous icebergs.

So we’re looking at the effect of about 1% of the earth’s water going into the sea (and that assumes none will go into groundwater or evaporate from the alleged overall increased temperatures).

The Earth’s surface is 510.1 million km², and land covers only 29% of it.  If you want to work out the effect of 24,064,000 km³ being added to 1,338,000,000 km³, it requires the formula for the volume of sphere:

That is a bit complicated, however, as the Earth isn’t perfectly spherical so the value for r isn’t constant to start with.

But whatever, it’s clear that the most that sea levels could rise even if all land ice melted is a few dozen centimetres, and for the reasons mentioned above, we doubt it will be by any significant amount at all.