"Study author Dr Svetlana Jevrejeva, NOC, said: “More than 600 million people live in low-elevation coastal areas, less than 10 metres above sea level.“In a warming climate, global sea levels will rise due to melting of land-based glaciers and ice sheets, and from the thermal expansion of ocean water.
“So sea level rise is one of the most damaging aspects of our warming climate.”
The study found a temperature rise trajectory of just 1.5C by 2100 will see average sea levels rise by up 1.7ft (0.52m).
But exceeding the UN 2C target by 2100 could see waters rise by 2.8ft (0.86m) or 5.9ft (1.8m) in a worst-case scenario."
As the website ipcc.ch informs us, in the worst scenario on the end of 21 century the average world temperature will increase about 6.4 degree of Celsius.
But what would be happened if the average world temperature would increase not 6.4 but 15 degree of Celsius?
We know that with global warming only ice on lands influences on sea level. The biggest lands covered by ice are: Antarctica and Greenland. Let's look at Greenland. The website tradingeconomics.com shows averate temperatures for Greenland which is shown below.
What about Antarctica?
Wikipedia informs us:
"The mean annual temperature of the interior is −57 °C (−70.6 °F). The coast is warmer; on the coast Antarctic average temperatures are around -10°C (in the warmest parts of Antarctica) and in the elevated inland they average about -55°C in Vostok."
It means, it is also below zero and Antarctic glacier should survives.
But, of course, Indonesians would have problem in this case. Their average temperature could increase until 40 °C. Average temperature in Indonesia, as the tradingeconomics.com informs is around 26 °C what is shown below in a picture taken from the mentioned website.
"5,000 years ago the Sahara deset was home to people, animals, and lush vegetation.
As recently as 5,000 years ago, one of the world’s driest and most uninhabitable places, the Western Sahara desert, was home to a vast river system that would rank as the world’s 12th largest drainage basin if it existed today.
Theories that the Sahara was once home to waterways that sustained life from rhinos to humans and various species of fish have gained traction in the last few years. In 2013, researchers argued that, based on computer modeling of the Sahara as it existed 100,000 years ago, monsoon rains would have been heavy enough to feed three main rivers. Some paleohydrologists believe these waterways are the key to the answer of how humans migrated out of central Africa."
And the Gobi desert was also full of life thousands years ago about which we are informed by scienceinpoland.pap.pl website:
"Many thousands of years ago life flourished in the Mongolian Gobi desert. Archaeologists from Wrocław discovered traces of a rich settlement from the period of the Stone Age."
Steam is excellent greenhouse gas, so the more clouds, the average temperature of the Earth will be higher. Ok, let average temperature to rise of 15 °C. It does not mean that average temperature in Indonesia will be 40 degree. Steaming water absorbs heat from the environment. In Indonesian area ocean water will evaporate cooling surroundings, and next, clouds will transport heat far away to Siberia or New Zealand and their condensing and rain will warm atmosphere and grounds there. It means, temperature in Indonesia could not change or increase a little but temperature in Antarctica could increase about dozens degree due to green house effect. Because of big amount of clouds in atmosphere causing greenhouse effect the temperature of the whole world could be evened out. The picture below taken from the website quora.com explains how green house effect works. Heat at infrared radiation trying to escape to cosmic space is reflected back by clouds. The more clouds the reflection stronger and temperature of surface higher. Probably there is optimal amount of clouds over Earth's surface for the most effective green house effect. Too many clouds reflect solar radiation back to cosmic space. Of course temperature of surface of the Earth will be not warming up without end. Because of the Stefan - Boltzmann law temperature will stabilize quite quickly.
Let's summarize what will happen when the greenhouse effect will be increasing.
1. Because of human production of carbon dioxide temperature of atmosphere increases.
2. Water from oceans steams more intensively. More water is collected in atmosphere.
3. Great clouds are created, Hadley cells become bigger and rains fall on deserts creating lakes and rivers there. Water enters into sand and soil to big depths. Desert sand grains are surrounded by bound water.
4. Ice of Antarctica, Greenland, Siberia melt creating wetlands and swamps there.
5. Temperature on the all of the world becomes almost equal.
6. Life flourishes and organisms collect water in their bodies. Because of abundance of water and carbon dioxide plants become larger and higher.
These six points could lead to lowering the sea level. New lands will be habitable. Thanks to the more fertile plant growth and animals, humanity will be able to eliminate the problem of hunger without using to chemistry and gmo.
Probably situation described above took place in history. This is commemorated in the South American myths described by Cornellia Petratu and Bernard Roidinger in the book "Die Steine von Ica: Protokoll einer anderen Menschheit", as well as in African myths popularized by Credo Mutwa and to David Icke. People survived it. It means that the temperatures were then bearable. Some inconvenience would be a permanent lack of the Sun in the daytime and stars and the Moon at night. The sky would be overcast all the time. But higher volcanic activity could be a threat to this state of affairs. Volcanoes introducing dust into the atmosphere would create condensation centers of water vapor, which would disturb the balance of water contented in the air and intensify rainfall. Rains would remove partially cloud cover, cloudless sky would be revealed, heat would be radiated into cosmic space and Earth would be cooled. And because of it rains would be more intense what could lead to great flood. Such a situation would last until the next level of equilibrium would be reached at much lower average temperature.