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→… oceans and marine life?
Now that the goals of the Paris Agreement have been set, the Glasgow climate talks should be about creating a more detailed roadmap of how to achieve them. Some important considerations will include how to agree on more effective near-term emission reductions. For example, transitioning away from fossil fuels, improving the use of energy, limiting deforestation, and converting net-zero pledges into action.
Now that the goals of the Paris Agreement have been set, the Glasgow climate talks should be about creating a more detailed roadmap of how to achieve them. Some important considerations will include how to agree on more effective near-term emission reductions. For example, transitioning away from fossil fuels, improving the use of energy, limiting deforestation, and converting net-zero pledges into action.
== <big>What is the climate crisis?</big> ==
== <big>What is the climate crisis?</big> ==
''In this section, we explore the phenomena known as “climate change”. What is it? What’s causing it? And why is it urgent?''
''In this section, we explore the phenomena known as “climate change”. What is it? What’s causing it? And why is it urgent?''
As a result of ocean temperatures warming, many marine species have changed their behaviour and location, bringing them into contact with different species, causing disruption to ecosystems and increasing the risk of spreading disease<ref>[https://www.ipcc.ch/srocc/ IPCC 2019 Special Report The Ocean and Cryosphere in a Changing Climate], SPM A4, A5 & A6</ref>.
As a result of ocean temperatures warming, many marine species have changed their behaviour and location, bringing them into contact with different species, causing disruption to ecosystems and increasing the risk of spreading disease<ref>[https://www.ipcc.ch/srocc/ IPCC 2019 Special Report The Ocean and Cryosphere in a Changing Climate], SPM A4, A5 & A6</ref>.
Many changes due to past and future greenhouse gas emissions are irreversible for centuries to millennia, especially changes in the ocean circulation, ice sheets and global sea level.
Scientists say that unless there are immediate, rapid and large-scale reductions in greenhouse gas emissions, this situation will soon become too severe to meet the Paris targets<ref name=":32" /> – this is why what we are experiencing now is a climate and ecological crisis.
= <big>Scenarios and pathways</big> =
'''What are the different temperature rise scenarios and climate mitigation pathways for the future, the challenges and uncertainties ahead?'''
=== <big>A. Climate models & projected changes in greenhouse gas emissions and atmospheric temperature</big> ===
“Climate models” are sophisticated computer simulations that are used to analyze the future impact of changes in greenhouse gas emissions on the Earth’s climate. They can also be used to investigate how policies and technologies can be used to mitigate climate change. Climate change '''mitigation''' refers to efforts to reduce, or prevent, the emission of greenhouse gases.
The latest IPCC report<ref>[https://www.ipcc.ch/report/ar6/wg1/ IPCC AR6]</ref> provided five possible scenarios for climate change based on scientific models. These outline the level of warming that can be expected in “very low” to “very high” emissions scenarios, depending on the level of CO<sub>2</sub> and other greenhouse gases emitted in the next decades.
The scenarios also vary depending on changes in population, land usage, trade and investment policies, our personal diets, and the efforts taken now to control emissions.
* '''In a “very high” emissions scenario, where the world continues on a carbon-intensive pathway, we would see CO<sub>2</sub> emissions roughly tripling from current levels by 2100 and warming of between 3.3-5.7°C by the end of the century.'''
* '''In a “high” emissions scenario, where very little action is taken to curb CO<sub>2</sub> emissions, we would see CO<sub>2</sub> emissions roughly doubling from current levels by 2100 and a warming of 2.8-4.6°C by the end of the century.'''
* '''In an “intermediate” emissions scenario, where CO<sub>2</sub> emissions remain at around current levels until the middle of the century and then decrease slowly, we would see warming of 2.1-3.5°C by 2100.'''
* '''In a “low” emissions scenario, where the world starts to take action in the 2020’s to limit CO<sub>2</sub> emissions, CO<sub>2</sub> emissions would reach net zero by 2075 and a warming of between 1.3-2.4°C by 2100.'''
* '''In a “very low” emissions scenario, CO<sub>2</sub> emissions decline rapidly from the early 2020s and reach net-zero around the year 2050, we would see a warming of 1.0-1.8°C by the end of the century.'''
In all the scenarios outlined by the IPCC, 1.5°C of warming is likely to be reached by 2040, representing increased risk to natural and human systems compared to the present time However, even keeping to within a 2°C target is still very dependent on the level of emissions produced over the next decade and 2°C of warming is only avoided in the low emissions scenarios.
=== <big>B.Challenges and trade-offs</big> ===
Without far-reaching policy, technology and behaviour changes, the world is on course for 3°C of warming or higher. A 3°C world is very different from the current one: with extremes of temperature come more pronounced risks of heat waves and drought, violent storms, rainfall and flooding, that will have serious consequences for ecosystems and societies around the world.
Deciding how to address the climate and ecological crisis is fundamentally about seeking to understand the challenges and trade-offs inherent in any scenarios.
In order to better understand these challenges and trade-offs, here we explore the internationally agreed Paris Agreement target to limit global warming to 1.5°C.
To limit global warming to 1.5°C, current global emissions of carbon dioxide need to be cut in half by 2030, reaching net-zero '''CO<sub>2</sub>''' emissions globally around the year 2050, as well as achieving large reductions in other greenhouse gas emissions such as methane and nitrous oxide. Taking '''equity''' into account means that richer countries should cut their emissions much more than poorer countries.
One concern is that large reductions in energy use could reduce living standards in industrialized, rich countries, as well as limit our ability to improve the living standards in poor countries. Improving living standards in poor countries will in some cases require increases in energy use and investment in efficient technology and public services
== <big>Glossary</big> ==
== <big>Glossary</big> ==