Global Warming: Truth or Myth?

In December 2014, fifty scientists and disseminators, members of the Committee for Skeptical Research, published a manifesto asking that those who question the theory of climate change and its anthropocentric origin not be called skeptics.

"Skepticism promotes scientific and critical research, and the use of reason in the examination of controversial and extraordinary claims. It is at the basis of the scientific method. Denialism, on the other hand, is the a priori rejection of ideas without objective consideration," reads the text, signed today by members of the world's most prestigious research centers.

In every conversation or article about climate change and its effects, there is always a voice that denies that the climate has been extraordinarily altered in recent decades or that, in any case, this is due to human action.

In an issue as complex as the planet's climate, with so many factors and consequences involved, of course studying climate change is not a simple matter, and yet, in recent years, the scientific community has increasingly fewer doubts.

"There is no reasonable doubt about the influence of human activity on the global climate, nor about the fact that this influence has consisted of an increase in the global average temperature," Carlos Duarte, professor and researcher at the Mediterranean Institute for Advanced Research, said.

The Fifth Assessment Report carried out by the IPCC and the organizers of the Paris Climate Summit pointed in the same vein.

Facing the arguments of the negationists, on their website you can find the most common arguments for denying climate change and what are the responses given by scientists to those arguments.

1. Climate change came to a halt in 1998

A report published by the British Hadley Center in 2008 showed that, according to the data, the planet had warmed only about 0.2 degrees a year from 1998 to 2008, which was interpreted by some analysts, and widely publicized, as global warming had practically stopped.

However, that was a rather naive way of interpreting the data. The reality is that in Hadley Center's own data one could see that the eight warmest years of the previous century and a half were, in order, 1998, 2005, 2003, 2002, 2004, 2006 and 2007.

Are they still those? No, not anymore. The 21st century accumulates a good number of record warm years: 2014 is the hottest year since action began in 1850.

2. Global warming can be explained by changes in solar activity

It is true that solar cycles, which last about 11 years, affect the Earth's temperatures and climate.

However, if that were the main reason, warming would be seen homogeneously in all layers of the atmosphere, and not much more noticeably in the lower layers in contact with the earth's crust, while the stratosphere cools down. "This shows the influence of greenhouse gases," explains IPCC member Jean Joucel.

3. Climate change prediction models not accurate enough

The scientists themselves recognize that, as prediction models, the forecasts of global warming for the next decades between now and the end of the 21st century have a certain degree of uncertainty.

However, they have been improved with each confirmed data, and they have been tested modelling climatic phenomena of the past, in such a way that they have proved to be very suitable for predicting also those that will come in the future, although they cannot contemplate unforeseen phenomena such as, for example, volcanic eruptions.

4. IPCC members have a conflict of interest

It is often argued that the scientists who participate in the IPCC are paid by governments, which implies that they can respond to interests beyond the veracity of the information and predictions they handle.

The truth is that the IPCC has a small staff of about 30 members, and the rest of the more than 800 participating scientists do so on a voluntary basis. Each one of them dedicates between four and five months of work to the accomplishment of each report, in addition to its habitual work.

The researchers come from countries all over the world and are replaced from one report to the next (from the fourth report to the fifth about 69% of the participants changed).

Of course, defending the independence and integrity of all scientists is impossible, but the system is designed to avoid the excessive influence of one person, to achieve the greatest possible consensus, and to promote the exchange of ideas and the inclusion of as many points of view as possible.

5. There is no scientific consensus about climate change and its anthropocentric origin.

This isn't true. 97.1 percent of the scientific studies published in the last two decades on climate change and that analyze its causes, point to the human being as the main culprit.

6. Global warming is a natural phenomenon

Solar activity, volcanic eruptions and ocean currents are phenomena that can affect the global climate, and have in fact done so in the past.

However, this is the first time in history that human activity is a central factor in this change. Among other conclusions, one of the IPCC reports stated that "since the 1950s many of the changes observed have been unprecedented in recent decades to millennia.

The atmosphere and the ocean have warmed, volumes of snow and ice have decreased, sea levels have risen, and concentrations of greenhouse gases have increased.

7. Climate change also has positive aspects

This argument mixes humor with resignation, but be careful, because altering global temperatures can have disastrous and unpredictable consequences: warmer summers and mild winters can alter agriculture and ecosystems, making certain species disappear, altering their balance, causing some food shortages and even increasing some diseases.