Pre industrial levels

"Pre-industrial levels" in the context of climate change typically refer to the state of the Earth's climate before the significant industrialization of the world, which began in the late 18th century. It's a baseline period used to compare current and future levels of greenhouse gases (like carbon dioxide, methane, and nitrous oxide) and global temperatures.

Usually, the pre-industrial period is considered to be the years before the widespread use of fossil fuels and the significant increase in human-made greenhouse gas emissions. The specific reference period can vary slightly, but it's often set to the mid-19th century or the late 18th century. Scientists use this period as a benchmark because it represents a time when human activities had a relatively minor impact on the Earth's climate compared to today. Comparing current conditions to pre-industrial levels helps us understand the extent of climate change and its associated impacts.

 

The Paris Agreement is an international treaty signed in 2015 that aims to combat climate change by limiting global warming to well below 2 degrees Celsius above pre-industrial levels, with an aspiration to limit it to 1.5 degrees Celsius. This means that countries that are party to the agreement have committed to taking actions to keep the increase in global average temperatures well below 2 degrees Celsius and to pursue efforts to limit the temperature rise to 1.5 degrees Celsius.

The reference to "pre-industrial levels" in the Paris Agreement is crucial because it sets a clear and scientifically based benchmark for measuring the extent of global warming. By striving to limit global warming to these levels, the agreement seeks to prevent the most severe consequences of climate change, such as more frequent and intense heatwaves, sea level rise, and disruptions to ecosystems.

To achieve these temperature targets, countries that are part of the Paris Agreement have made various commitments to reduce greenhouse gas emissions, transition to cleaner energy sources, and enhance climate resilience. The agreement represents a global effort to address climate change and protect the planet for future generations.

 

 Paris Agreement, the focus is on keeping global temperatures "well below" 2 degrees Celsius "above" pre-industrial levels, with an aspiration to limit the increase to 1.5 degrees Celsius "above" pre-industrial levels. The use of "above" in this context means that the aim is to prevent global temperatures from rising to a level that exceeds 2 degrees Celsius or 1.5 degrees Celsius higher than what they were during the pre-industrial period. In other words, the goal is to keep temperatures below these thresholds to avoid the most severe impacts of climate change.

 

The term "pre-industrial temperature" typically refers to the global average temperature before the widespread industrialization of the world, which began in the late 18th century. While there is no specific single temperature value for pre-industrial times, it's often referenced as a range.

Scientists estimate that the global average temperature during the pre-industrial period, which is usually considered to be the mid-19th century or the late 18th century, was approximately 0.6 to 0.8 degrees Celsius lower than the late 20th-century average. This means that temperatures in the mid-19th century or late 18th century were roughly 0.6 to 0.8 degrees Celsius cooler than the average temperature between 1961 and 1990, which is a common reference period in climate research.

So, when we talk about limiting global warming to well below 2 degrees Celsius above pre-industrial levels, it means trying to prevent the Earth's average temperature from increasing by more than 2 degrees Celsius compared to this historical baseline.

The historical baseline for pre-industrial temperatures is often considered to be the period before the widespread industrialization of the world, which is typically estimated as the mid-19th century or the late 18th century. During this period, the global average temperature is estimated to have been roughly 0.6 to 0.8 degrees Celsius lower than the late 20th-century average.

So, the range for this historical baseline would be approximately 0.6 to 0.8 degrees Celsius lower than the late 20th-century average temperature. This baseline is used as a reference point to measure the extent of global warming and climate change, with efforts to limit global warming to well below 2 degrees Celsius above this historical baseline, as outlined in the Paris Agreement.

The historical baseline temperature is estimated to be roughly 0.6 to 0.8 degrees Celsius lower than the late 20th-century average temperature. So, if the late 20th-century average temperature was, for example, 14 degrees Celsius, then aiming to keep temperatures below 2 degrees Celsius above pre-industrial levels means limiting global warming to below 16 degrees Celsius..

 

The historical baseline temperature is estimated to be roughly 0.6 to 0.8 degrees Celsius lower than the late 20th-century average temperature, which is often cited as approximately 14 degrees Celsius. So, when aiming to limit global warming to well below 2 degrees Celsius above the pre-industrial baseline, the target is to keep temperatures below approximately 15.2 to 15.8 degrees Celsius, not 16 degrees Celsius.

The Paris Agreement itself is the main international climate agreement that was adopted in 2015 during the 21st Conference of the Parties (COP21) to the United Nations Framework Convention on Climate Change (UNFCCC). However, under the Paris Agreement, various subsidiary agreements, initiatives, and commitments have been made to enhance global efforts to combat climate change. Some of these include:

1. Nationally Determined Contributions (NDCs): Each participating country in the Paris Agreement is required to submit its NDC, outlining its specific climate action plan and emission reduction targets. These NDCs can be updated and strengthened over time.

2. Long-Term Low-Emission Development Strategies (LT-LEDS): Countries are encouraged to develop long-term strategies to transition to a low-carbon and climate-resilient future. These strategies provide a roadmap for achieving long-term climate goals.

3. Financial Commitments: Developed countries pledged to provide financial support to developing nations to help them mitigate and adapt to climate change. The goal is to mobilize climate finance to reach $100 billion annually by 2020.

4. Technology Transfer and Capacity Building: The Paris Agreement promotes the sharing of clean energy technologies and capacity-building efforts to assist developing countries in their climate actions.

5. Global Stocktake: The agreement establishes a process for periodic global stocktakes to assess collective progress towards the climate goals. This helps to determine whether further action is required.

6. Transparency Framework: The agreement includes provisions for transparency and accountability, requiring countries to regularly report on their emissions and progress in implementing their NDCs.

7. Loss and Damage: The agreement acknowledges the importance of addressing loss and damage associated with the adverse effects of climate change, particularly in vulnerable and developing regions.

8. Global Climate Action: The Paris Agreement has facilitated a wide range of initiatives, partnerships, and actions by non-state actors, including cities, businesses, and civil society, to complement the efforts of national governments.

These are some of the key elements and agreements that have emerged as part of the Paris Agreement's framework to address climate change on a global scale. Each COP meeting subsequent to COP21 has furthered discussions and actions related to these components.

As of my last knowledge update in September 2021, the global average temperature was already approximately 1.2 degrees Celsius above pre-industrial levels. This means that in order to limit global warming to below 2 degrees Celsius above pre-industrial levels, we would need to ensure that the global average temperature does not increase by more than an additional 0.8 degrees Celsius from that point.

I apologize for any confusion. You are correct; as of my last knowledge update in September 2021, the global average temperature had risen by approximately 1.2 degrees Celsius above pre-industrial levels. Efforts to limit global warming to below 2 degrees Celsius (and ideally to 1.5 degrees Celsius) are aimed at preventing more significant and potentially dangerous impacts of climate change.

The concern is that even a 2-degree Celsius increase above pre-industrial levels can lead to substantial consequences, including more frequent and severe heatwaves, sea level rise, disruptions to ecosystems, and greater risks to vulnerable communities. Additionally, the scientific consensus has increasingly shown that limiting warming to 1.5 degrees Celsius, if feasible, would result in fewer and less severe impacts compared to a 2-degree increase.

Efforts to limit global warming involve reducing greenhouse gas emissions, transitioning to cleaner energy sources, and enhancing climate resilience. The goal is to minimize the risks associated with higher temperatures and mitigate the worst effects of climate change, which could become increasingly problematic as temperatures rise further.

 If the global average temperature has increased by approximately 1.2 degrees Celsius above pre-industrial levels, and if we consider pre-industrial levels to be around 14 degrees Celsius, then the current global average temperature would be around 15.2 degrees Celsius. To limit global warming to below 2 degrees Celsius above pre-industrial levels, we would aim to ensure that the temperature does not exceed 16 degrees Celsius. This aligns with the goals of the Paris Agreement to prevent the most severe impacts of climate change. Indeed, even a relatively small increase in global average temperature, such as the 1.2 degrees Celsius observed above pre-industrial levels, can have significant and wide-ranging impacts on the environment, ecosystems, and human societies. These impacts include:

1. More Frequent and Severe Heatwaves: Higher temperatures can lead to more frequent and intense heatwaves, which can have serious health consequences and strain energy and water resources.

2. Sea Level Rise: Warming temperatures contribute to the melting of glaciers and the thermal expansion of seawater, resulting in rising sea levels. This poses risks to coastal communities and ecosystems.

3. Changing Weather Patterns: Climate change can alter weather patterns, leading to more extreme weather events such as hurricanes, droughts, and heavy rainfall events.

4. Disruption of Ecosystems: Species may struggle to adapt to rapidly changing temperatures, leading to disruptions in ecosystems, potential extinctions, and shifts in the distribution of plants and animals.

5. Agricultural Impacts: Changes in temperature and precipitation patterns can affect crop yields, potentially leading to food security challenges.

6. Impacts on Water Resources: Changes in temperature and precipitation can affect water availability and quality, with consequences for drinking water supplies and agriculture.

7. Health Risks: Higher temperatures can exacerbate health issues, particularly for vulnerable populations, and can lead to the spread of diseases carried by insects (like malaria and dengue).

It's important to recognize that these impacts are not uniform; they can vary regionally and affect different communities and ecosystems in different ways. This is why there is a global effort to limit further warming and mitigate these risks by reducing greenhouse gas emissions and adapting to the changes that are already occurring.

 

The future global temperature increase under a "business-as-usual" scenario depends on various factors, including future greenhouse gas emissions, climate sensitivity, and policy actions. A "business-as-usual" scenario typically assumes that current trends in greenhouse gas emissions continue without significant efforts to reduce them.

While I cannot provide real-time or future climate projections, I can offer some general insights based on previous climate model projections and scenarios:

1. 2030: Under a "business-as-usual" scenario, global temperatures are expected to continue rising. By 2030, the increase in temperature is likely to be in the range of 1.5 to 2.0 degrees Celsius above pre-industrial levels or possibly higher. This range represents a significant departure from the goals of the Paris Agreement, which aims to limit warming to well below 2 degrees Celsius above pre-industrial levels.

2. 2050: If greenhouse gas emissions continue on a business-as-usual trajectory, global temperatures are projected to continue rising. By 2050, temperatures could potentially be in the range of 2.5 to 3.5 degrees Celsius above pre-industrial levels or even higher. Such an increase would have profound and potentially catastrophic consequences for the planet's climate and ecosystems.

It's important to note that these projections come with considerable uncertainty, as future emissions and climate responses are subject to various factors, including policy decisions, technological developments, and societal changes. Efforts to limit emissions and transition to a low-carbon economy can help mitigate these temperature increases and their associated impacts. International agreements like the Paris Agreement aim to steer global efforts away from a business-as-usual scenario toward a more sustainable and climate-resilient future.