Climate change

Microclimatev00.50 credits/fixed

Responsible:Niccolò Calandri

To calculate Climate change Risk (focusing on warming), we use the variable [Copernicus Climate Data Store (CDS)]:

Monthly mean of daily mean temperature: monthly average temperature (°C) near the ground (2m) By calculating the annual mean temperature for each future year and comparing it with that of a reference period (1950-1970), we can measure the effect of climate warming and the resulting risk.

The methodology described for defining Climate Change Risk levels based on annual mean temperature increase ( $\Delta T$ ) relative to a historical reference period is conceptually aligned with the approach used by the international scientific community, particularly the Intergovernmental Panel on Climate Change (IPCC). The IPCC is the United Nations body responsible for assessing the science related to climate change. Its reports represent the primary and most authoritative reference in this field. The methodology of using temperature anomalies to communicate warming and associated risks is a pillar of modern climatology.

The most important documents providing the scientific basis for this risk classification are the IPCC assessment reports.

Climate Change 2021: The Physical Science Basis This report is the most current and comprehensive source on the physical science of climate change. It clearly establishes the connection between greenhouse gas emissions, rising global mean temperatures, and intensifying extreme weather events (heat waves, droughts, heavy rainfall). Chapter 11 ('Weather and Climate Extreme Events in a Changing Climate') is particularly relevant, as it analyzes how the frequency and intensity of these events change at specific levels of global warming (e.g., +1.5°C, +2.0°C, etc.), providing the scientific basis for the listed risk descriptions.
Climate Change 2022: Impacts, Adaptation and Vulnerability This is the crucial reference that directly links warming levels ( $\Delta T$ ) to specific impacts and risks for human and natural systems. The 'Reasons for Concern' (RFCs) concept, introduced in previous reports and updated here, visually synthesizes how risks in different categories (e.g., unique and threatened systems, extreme weather events) increase from 'undetectable' to 'very high' with increasing temperature. This framework is the most direct scientific representation of the A to F risk scale.
Global Warming of 1.5 ºC This special report was fundamental in defining the +1.5°C threshold as a critical point. It analyzes in detail the difference in impacts and risks between a +1.5°C and a +2.0°C world, providing the scientific evidence justifying the distinction between risk levels C, D and E. It demonstrates how an increase of half a degree Celsius can mean crossing 'tipping points' for ecosystems like coral reefs and a dramatic increase in risks to water and food security. Beyond the IPCC reports, which are syntheses of thousands of studies, the original scientific literature contains numerous papers supporting this methodology.
Allowable CO2 emissions based on regional and impact-related climate targets This study illustrates how different levels of global warming (e.g., 1.5°C vs 2°C) translate into very different regional impacts, particularly regarding temperature extremes and precipitation. It supports the idea that a global metric like mean ΔT is an effective indicator for localized and increasing risks.
Tipping elements in the Earth's climate system This is a seminal article that introduced and mapped 'tipping points' of the climate system (e.g., Greenland ice sheet collapse, Amazon rainforest dieback). The study associates activation of these tipping points with specific levels of global warming, providing a robust scientific basis for descriptions of higher risks (D, E, F) in the considered scale. In summary, our methodology is an operational and founded simplification of scientific principles established by the IPCC and broader climatological literature. The cited documents provide quantitative and qualitative bases for associating specific temperature increases with an increasing scale of physical risks for the environment and society.

Data Sources & References

Sources

WRD_CDSCA_99

Methodology

The methodology described for defining Climate Change Risk levels based on annual mean temperature increase ( $\Delta T$ ) relative to a historical reference period is conceptually aligned with the approach used by the international scientific community, particularly the Intergovernmental Panel on Climate Change (IPCC).
The IPCC is the United Nations body responsible for assessing the science related to climate change. Its reports represent the primary and most authoritative reference in this field. The methodology of using temperature anomalies to communicate warming and associated risks is a pillar of modern climatology.

The most important documents providing the scientific basis for this risk classification are the IPCC assessment reports.
• [Climate Change 2021: The Physical Science Basis](Climate Change 2021: The Physical Science Basis)
This report is the most current and comprehensive source on the physical science of climate change. It clearly establishes the connection between greenhouse gas emissions, rising global mean temperatures, and intensifying extreme weather events (heat waves, droughts, heavy rainfall). Chapter 11 ('Weather and Climate Extreme Events in a Changing Climate') is particularly relevant, as it analyzes how the frequency and intensity of these events change at specific levels of global warming (e.g., +1.5°C, +2.0°C, etc.), providing the scientific basis for the listed risk descriptions.
• [Climate Change 2022: Impacts, Adaptation and Vulnerability](Climate Change 2022: Impacts, Adaptation and Vulnerability)
This is the crucial reference that directly links warming levels ( $\Delta T$ ) to specific impacts and risks for human and natural systems. The 'Reasons for Concern' (RFCs) concept, introduced in previous reports and updated here, visually synthesizes how risks in different categories (e.g., unique and threatened systems, extreme weather events) increase from 'undetectable' to 'very high' with increasing temperature. This framework is the most direct scientific representation of the A to F risk scale.
• [Global Warming of 1.5 ºC](Global Warming of 1.5 ºC)
This special report was fundamental in defining the +1.5°C threshold as a critical point. It analyzes in detail the difference in impacts and risks between a +1.5°C and a +2.0°C world, providing the scientific evidence justifying the distinction between risk levels C, D and E. It demonstrates how an increase of half a degree Celsius can mean crossing 'tipping points' for ecosystems like coral reefs and a dramatic increase in risks to water and food security.
Beyond the IPCC reports, which are syntheses of thousands of studies, the original scientific literature contains numerous papers supporting this methodology.
• [Allowable CO2 emissions based on regional and impact-related climate targets](Allowable CO2 emissions based on regional and impact-related climate targets)
This study illustrates how different levels of global warming (e.g., 1.5°C vs 2°C) translate into very different regional impacts, particularly regarding temperature extremes and precipitation. It supports the idea that a global metric like mean ΔT is an effective indicator for localized and increasing risks.
• [Tipping elements in the Earth's climate system](Tipping elements in the Earth's climate system)
This is a seminal article that introduced and mapped 'tipping points' of the climate system (e.g., Greenland ice sheet collapse, Amazon rainforest dieback). The study associates activation of these tipping points with specific levels of global warming, providing a robust scientific basis for descriptions of higher risks (D, E, F) in the considered scale.
In summary, our methodology is an operational and founded simplification of scientific principles established by the IPCC and broader climatological literature. The cited documents provide quantitative and qualitative bases for associating specific temperature increases with an increasing scale of physical risks for the environment and society.