BlogBrief summary to climate change
Introduction to climate change
Changes in weather patterns and continuing fluctuations in the atmosphere’s temperatures are generally believed to be attributed to climate change. It can be due to natural causes such as below:
- sun’s activity,
- plate tectonics (shifts in Earth’s crust),
- volcanic eruptions, etc.
However, the progress of humankind and technological development not only brought prosperity and increased quality of life in some parts of the world but also led to negative consequences for the environment. This is predominantly due to the fact that the main sources of energy are fossil fuels like coal, oil, and gas. By burning them, greenhouse gas (GHG) emissions are emitted into the atmosphere, which acts as an additional layer for the Earth (like an extra blanket) and does not allow heat to escape easily, raising the temperature.
What happens if the issue is not addressed?
The consequences of climate change vary and come in diverse ways. For example:
- heavy rainfall days
- extremely hot weather
- droughts
- ice melting
- increasing sea levels
- wildfires
- flooding
- and many others
These affect humans but also all living creatures on the planet in such a way that communities are displaced, biodiversity is reduced, famine is happening, etc.
Importance of numbers 1.5 and 2
To prevent and mitigate the above undesirable events from happening, the Paris Agreement, which is a legally binding international treaty on climate change, was signed by 196 Parties at the UN Climate Change Conference (COP21) in 2015. The set goal was to limit global warming to well below 2°C above pre-industrial levels and to pursue efforts to limit the temperature increase to 1.5°C above pre-industrial levels. According to the Emissions Gap Report 2023, which was developed and published by the United Nations Environment Programme, GHG emissions reached a new high in 2022. In September 2023, global average temperatures were 1.8°C above pre-industrial levels [5].
The Intergovernmental Panel on Climate Change (IPCC) formally defines the crossing of a threshold as the midpoint of the first 20-year period with mean temperatures above that threshold [4]. This statement can be broken down as follows:
- Crossing point: This refers to the moment when global temperatures surpass the aforementioned threshold, i.e. 1.5°C or 2°C above pre-industrial levels.
- Midpoint: Once the temperatures have consistently remained above the threshold for a certain period, usually 20 years, the midpoint of this period is identified. This midpoint represents the approximate time when the threshold was initially crossed, marking a significant shift in climate conditions.
- First 20-year period: To establish a clear trend and confirm that the threshold has indeed been crossed, scientists typically look at the first 20 years of sustained temperature elevation above the threshold. This period provides a sufficient timeframe to assess the climate’s response to increased warming.
- Consistently above the threshold: It is important that during this 20-year period, the global temperatures remain consistently above the specified threshold. This consistency ensures that the crossing point is accurately identified and not just a temporary fluctuation in temperatures.
In summary, the statement emphasizes the specific criteria used by IPCC to define when a temperature threshold has been crossed, focusing on sustained elevation above the threshold for a defined period, with the midpoint of this period serving as the crossing point.
Disproportionality and inequality in GHG emissions
According to the findings of “Emissions Gap Report 2023: Broken Record” the new record for GHG emissions was set in 2022 and collectively, the G20 currently account for 76% of global emissions [5]. Furthermore, there is a disproportionate contribution to GHG emissions from different countries, which shows inequality that is present in the world. For instance, the United States of America, whose population is 4% of the global population, in 2021 had 11% of the global GHG emissions.
No time to waste
Without increased and urgent mitigation ambition in the coming years, leading to a sharp decline in greenhouse gas emissions by 2030, global warming will surpass 1.5°C in the following decades, leading to irreversible loss of the most fragile ecosystems, and crisis after crisis for the most vulnerable people and societies. In order to have a chance in reaching the goal of the Paris Agreement meaningful and strong actions need to be taken by implementing net-zero targets.
References
- What Is Climate Change? | United Nations
- What is net zero? | National Grid Group
- What is ‘net zero’, and how can we get there? | Greenpeace UK
- “The Global Climate 2011-2020”, WMO
- Emissions Gap Report 2023: Broken Record
- Explained: The 1.5 C climate benchmark | MIT News | Massachusetts Institute of Technology
- When scientists say the Earth has warmed by 1° Celsius, which parts of the planet are being measured? | MIT Climate Portal