Within the framework of its adaptation strategy to climate change, the EU adopted the upper limit of 2 degrees C (UNFCCC, Cancun 2010) as an allowable increase concerning the average air temperature of the planet. This decision aims at compulsorily reducing the most serious risks from climate change. The UN Conference on Climate Change (UNFCCC COP21 2015) emphasizing the holding of the increase in the global average temperature to well below 2 degrees C above pre-industrial levels by reducing emissions to 40 Gt or to pursuing efforts to limit the temperature increase to 1.5 degrees C. Taking into an account the COP21 climate change strategy, we consider five significant cases. The first one for the current climate conditions (corresponds to a 0.8 degrees C global warming above the pre-industrial level), the model based on logistic equation provides a solution according which, within the next 95 years, the sea level will rise up to +5 m and stabilize at +6 m level within a 150-year relaxation time. The second one, if global warming could be reduced of 28.5 times to the value of global average temperature 0.028 degrees C, the sea level would stabilize to the current value of 0.21 m. The third-if the global average temperature will increase to 1.5 degrees C above the pre-industrial era, this will lead to an inevitable rise of the global sea level by +11.25 m. The fourth-if Earth's global average temperature increases to 2 degrees C above the pre-industrial era, this will accelerate the sea-level rise up to +15 m. The fifth-a realistic level of the global average temperature increase to 3 degrees C will lead to sea-level rise (SLR) by +22.5 m. This can happen from 100 years up to 250 years and can be associated with carbon dioxide emission and methane blowout from the Ocean. Taking into an account the Max Planck Institute for Chemistry climate model based on dust emission in atmosphere with +4 degrees C Global Warming up to 2050 year, we can predict the very fast SLR up to 30 m. Exceeding the critical level of global average temperature +1.30(6)degrees C or the +9.8 mSLR will destabilize the Earth climate system and could provoke falling in the next Ice Age. This value is 1.53 times less than the +2 degrees C Global Warming level adopted in Paris (UNFCCC COP21 2015) as acceptable for sustainable economic development. Antarctica ice mass loss and Greenland ice mass loss are going with the rate of 2.03 and 1.74, within five-year period (August, 2010-2015) and estimated as total 589.9 Gt in 2016 that will contribute SLR the 1.628 mm per year. The main question is can the national mid-century strategies for the transition to low-emission economies stop the SLR before it will be too late.