Climate Change

This section attempts to talk about climate change to better explain what is happening around us and why it matters for you.

Climate change 101

Nineteen of the hottest 20 years among the last 140 have been recorded consecutively since 2001.

Although the climate on earth has always undergone changes attributable to small variations in the Earth’s orbit, the current global warming trend and the consequent climate change is, according to 97% of climate scientists, the result of human activity.

. The birth and growth of industrial activities have in fact significantly increased the levels of carbon dioxide in the atmosphere, as well as those of other greenhouse gases (water vapour; methane; dinitrogen oxide; chlorofluorocarbons). This change of gas concentrations has trapped the heat, generating the so-called greenhouse effect.

. The consequences of these changes are difficult to predict, but below we list some of the most obvious.

One of the main consequences of the greenhouse effect is the rise in average temperatures, which today is about +1°C compared to the end of 1800. It is likely that temperatures will increase and reach +1.5C between 2030 and 2050.

Another consequence of the greenhouse effect is the rising of sea levels, which has grown by about 20 cm in the last 100 years, doubling in speed in the last 20.

Due to the balance broken by the greenhouse effect, the number and frequency of extreme weather events such as hurricanes, droughts, fires and floods have increased.

The oceans have absorbed much of this warming, causing an increase in temperatures of more than +0.4°C since 1969. This increased the acidity of their surface by about 30%.

The Arctic and Antarctic ice sheets have been melting every year, losing an average of more than 400 billion tons of ice per year between 1993 and 2016.

Glaciers have undergone an inexorable process of retreat into mountain ranges around the world, from the Alps to the Himalayas. At the same time, over the past 50 years, the amount of snowfall has decreased throughout the northern hemisphere.

The Paris Agreement (2015), which was signed by the member states of the United Nations Framework Convention on Climate Change (UNFCC), has among its main objectives that of pursuing efforts to limit global temperature rise to +1.5°C. In 2018, the IPCC (the UN’s Intergovernmental Panel on Climate Change) published a report on the impacts of global warming and trends in greenhouse gas emissions, further examining the risks and consequences of inaction in relation to the threat of climate change. According to the IPCC, the projections obtained from the models indicate that climate impacts will be greater for a global heating of +1,5° C, compared to the current situation, further increasing in the event of a 2° heating. The report then identifies significant differences in regional climatic characteristics that will be reflected in different climatic events. These include increases in:

a) average temperature in most land and ocean areas;
b) heat peaks in most inhabited regions;
c) heavy rainfall in different regions;
d) the probability of drought and scarcity of rainfall in numerous regions.

Limiting this temperature increase to +1.5°C instead of to +2°C will be essential in reducing these risks. In fact, the need for adaptation will be inferior for a total warming of +1.5°C compared to +2°C. Human actions will be vital in order not to exceed the limit of +1.5°C. We can achieve this by reducing net anthropogenic CO2 emissions by about 45% by 2030, compared to 2010 levels, and by reaching net zero around 2050. If we consider instead the limit as +2°C, emissions will have to decrease by about 20% by 2030, reaching net zero around 2075.



Sources
1. https://climate.nasa.gov/
2. https://www.climate.gov/
3. https://www.carbonbrief.org/
4. https://ipccitalia.cmcc.it/
5. https://ipcc.ch/
6. https://www.sisclima.it/wp-content/uploads/2019/07/SR15_SPM_ita.pdf