In the previous articles I wrote about this subject, I’ve been exposing some data and facts that make me believe that global warming is true, although there are some groups of individuals claiming it is a hoax – “Global warming I: Is it true or is it a hoax?”. In my second article, “Global warming II: The polar ice caps and the sea”, I presented more concrete data regarding the thawing of the polar ice caps, the sea level rise and its acidification. In the third article I wrote about the polemic controversy with the opposers of this theory – “Global warming III: The opposers and the controversies“. In this last article about this subject I’m going to talk about the perspectives of the defenders of this theory with the climate models and our future.
The truth is most of the scientists defend that we are really before a scenario of global warming, which severity would be between moderate to catastrophic, depending on the human response to the CO2 emission issues.
We may be at a risk that we can reach such a scenario we wouldn’t be able to invert the process. For instance, the polar ice caps help to reflect some of the solar energy, while the dark blue of the oceans are absorbing that energy. With the melting of the polar ice caps, the area that reflects the solar energy will decrease, increasing the area of the seas, thus increasing the absorption of solar energy. This way, the seas will warm faster, accelerating the melting of the polar ice caps until we reach a point the process will be so fast that climate changes could be sudden and catastrophic.
Climate models, the rise of temperatures and sea levels:
Many scientists are studying several climate models using most of the atmospheric and land surface variables we know today, forecasting future climate changes through a complex set of mathematical algorithms. However a calculation error percentage should always be considered, of course. Therefore, it’s normal to find different possible scenarios as many variables could vary in a way they will differ from the initially estimated values. For instance, unexpected changes in the emissions of greenhouse gases, during the future years under study, will have an impact in the climate models forecasts.
The following chart shows some global warming projections until 2100:
In this predictions is possible to see different results according to the models created by different entities. However, all these projections show an increase of temperature between 2ºC and 5ºC. Even in the most optimistic scenario, an increase of 2ºC is high enough to be considered as dangerous. In the worst scenario, let’s just remember the heat wave on 2003 which killed many people in Europe, specially in France.
In this second graphic we have a broader climatic model where we can see the forecast of temperature changes all around the globe:
Both graphics assume that there will be no changes in human behaviour regarding the emissions of CO2!
In another graphic, source EPA / IPCC, we can see three possible scenarios till 2099. In line B1 we have a scenario of low emissions of CO2, in line A1B a scenario of mid-high emissions and, in the worst case, line A2 with high emissions.
Even being these models subject to errors, I agree that this data is really of concern. I already wrote about the impact of the warming in the ice caps and in the seas and the average sea level rise projections are also serious, as you can see in the following graphic:
Once again, let’s remember that these are just projections and subject to errors. From the different observed scenarios, until 2100 we may have a rise between 0.2m and 2m. In the optimistic scenario, with a rise of 0.2m we shall keep having flood problems and the sea destroying and invading coastal areas as we seen in this current year of 2014. And this scenarios could get worse! On the other hand, a rise of 2m will have a dramatic impact with the seas advancing inland and causing many locations by sea-side to become submerged. For instance, in Portugal, in the county of Lisbon, most of the down-town of Lisbon, Algés, Cascais, Carcavelos, Estoril, among many other coastal locations will become under water and completely uninhabitable.
Is not a new to know that the polar beer is in danger of extinction. In an excellent BBC documentary, “BBC The truth about climate change Part I”, from where I also took some information for these articles, this fact is very clearly shown: The polar beer is at a great risk of extinction because of the thawing of the polar ice caps. This issue makes much harder to a female beer to hunt food for her cups, decreasing the changes of their survival. Scientists say that the number of poler beers are decreasing, as well as their cups health.
With the acidification of the seas, there are many endangered marine species, specially the organisms that rely on calcium carbonate such as corals, clams with shell, among others, as I already referred in the second post about this theme. The organisms are at the base of the food chain for many other marine animals. This situation will come to affect us, humans, as many populations depend on fishing in order to survive.
There are many other endangered species, but these are the ones whose impact could be more direct. Lately, considering this theory as real and if we fall into extreme conditions, it could be us, humans, to be endangered by living in a much warmer and hostile planet.
True or a hoax, the fact is that even a considerable number of sceptics don’t deny we are experiencing climate changes, although they consider them as normal and without serious consequences. But the temperature and sea level measurements, the observation of extreme weather conditions and the thawing of the polar caps are facts that should make us think and reflect for a while.
If all this theory is nothing else but a hoax, then something is happening to our planet. Is it temporary? Are we in some activity peak that will normalize? It will be something that it won’t really affect us at all? Well, in this case we might be having concerns in vain.
But, and if it is true? And if we keep going emitting huge amounts of CO2 to the atmosphere? Won’t we be sentencing mankind to its doom?
In one of the documentaries I watched when I studied this theme – Head to Head – Climate change: Fact or fiction? – in the ending, during the audience questions, one of the spectators made an excellent question: “Let’s consider the following propositions that the global warming is caused by man make sources. Some people will say this proposition is probably correct, you would say this proposition is probably not correct. If the statement is true there’s a catastrophic effect for the poorest people in the world (…) and thousand people die would you be able to take that into your conscious? (…)”
Honestly, I would like to make the same question to all global warming sceptics. It’s up to each one of us to believe or not in this theory but shouldn’t we all take this subject more seriously?