Presentation - how the global warming will change the world in the future?

I am going to talk about what the global warming is, how it will change our world in the future and make sure if it is a fact.
Global warming is the increase in the average temperature of the Earth caused by greenhouse effect ? that is concentration of carbon dioxide, water vapor and methane in atmosphere and formation impervious layer around our planet. It has been especially noticed during the last 100 years when the industrial era had begun and the temperature had changed about 0.7 degrees Celsius.
The results of it might be various.
Firstly, the glacier will be melting what will carry out to the extermination of some animal species particularly the polar ones and rising sea levels which will cause flooding in lower situated areas.
On the other hand, the spread of desert regions will reduce the number of places which are suitable for people to live.
Secondly, most of sea animals will become extinct because of ocean acidification caused by dissolving carbon dioxide in water.
What?s more, due to higher temperature, there will be probably no significant frosts in winter what will allow more viruses and bacteria to survive and evolve creating new kinds of illnesses.
Finally, there will be a rise of destructive solar activity.
However, there are more and more scientists which try to convince people that the global warming is only a great way to earn money. They state that there was a similar increase of temperature in the Middle Ages, so we don?t have a reason to be anxious about the life on the Earth in the future. Especially that after that warm period of time became a little ice age and these climate changes are usual. They also claim that emission of carbon dioxide to atmosphere by people is inessential ? smaller than produced by all volcanoes. Last but not least, they say that the most important greenhouse gas is a water vapor, which clouds are made of, so they reflect the sunlight getting through to the Earth.
To sum up, should we believe that the global warming is a fact or should we believe that we are deluded by world organizations such Greenpeace and other of this kind? I think everybody can judge themselves, but on the other hand, could we be absolutely sure what the truth is? I think, in case of the global warming problem would be real, we should take care of our planet in every way we can.
Thank you.