2020s is the milestone decade determining which world we will live in in the next 100 years.
Since the last official IPCC Report in 2014, the world has changed dramatically with the presence of a global pandemic, a recorded wildfire in the U.S. history, and a historical Trade War between the two strongest global economies. Extreme weather events and changes in the way countries consume products could lead to a dramatic shift in the long-term global climate and our process to mitigate greenhouse gases.
As a result, the IPCC 6th Assessment Report - the latest public-accessible, official, and most reliable global environment analysis - has been released in August 2021 to address all kinds of questions related to climate change, ranging from verification to updates about our current stages of achieving the century sustainability goals.
We have observed that, outside in the media, political discussions, or even scientific community, there are several contradictory opinions and statistics regarding the presence and intensity of global warming (potential temperature increase, the carbon level will reach until the end of 2100, etc.). Acting as the collective intellectual merits of global scientists and policy makers, it is very important that the IPCC Report can reach and spread the necessary environmental knowledge to anyone in the world.
Below is a graph depicting the five different SSP scenarios (Shared Socio-Economic Pathway) and their consequences to CO2 level. It can be seen that all scenarios result in the same CO2 concentration until 2020-2025, and branch later in the years. The year 2020-2030 will show us what exactly scenario we are in and the effectiveness of our current practices. Next decade will be a critical and vulnerable one that we need to pay attention to.
Fig 1. CO2 concentration simulated in five different scenarios (source: IPCC 6th Assessment Report) 
From 1990 until now, the IPCC has released six Assessment Reports, each report contains substantial improvements from the previous one. In this 6th report, five scenarios are defined based on the Shared Socioeconomic Pathway (SSP 1 to 5) and Representative Concentration Pathway (denoted as 1.9, 2.6, 4.5, 7.0, 8.5, which is the radiative forcing estimated in 2100 for each scenario - W m^-2). Here is the breakdown meaning of the scenario abbreviation in Figure 1:
SSP1-1.9: The world is under a sustainable development with enough care for the environment and energy conservation. This is the 1.5C increase target .
SSP1-2.6: This scenario corresponds to the 2C warming world, in which the socio-economic still remains SSP1 .
SSP2-4.5: Social issues such as environmental degradation and income inequality still persists, worse than SSP1 scenario .
SSP3-7.0: Worse scenario than SSP2 in which countries care more about their own economics and benefits than the environment. Regional conflicts make countries be more focused on regional issues .
SSP5-8.5: The worst scenario in which high fossil fuel usage persists throughout the 21st century .
Going through this explanation, what scenario do you want to live in? I guess the answer is the same across the world: We all want a normal life that is better or at least equal to SSP1-1.9.
Switching from SSP5 to SSP1 is not easy like switching the light. In fact, we might never be able to come back to the previous world once climate change has gone too far. Extreme elevated CO2 level could lead to irreversible changes in ocean biochemistry on centennial to millennial time scales. Under SSP1-2.6, the ocean might be 2-4 times warmer than the 1971-2018 change, and this magnitude gets to 4-8 times warmer under SSP5-8.5. There is a very high confidence in global ocean temperature and deep ocean acidification might not be reverse in a human lifetime .
We cannot deny the role of ocean and land ecosystems in converting CO2 to other harmless forms of carbon. In fact, 70% of CO2 emitted is fixed by natural-based solutions; however, there will be a point in which natural carbon sinks might be saturated and cannot catch up with the rate of CO2 emission. The capacity to store carbon gradually decreases as we move to more extreme future scenarios, eventually will decrease in half if SSP5 is the reality (Figure 2). As a result, the only way to sustainably remove air CO2 is reducing emission; the nature cannot tolerate us forever and we will have to pay the price for disturbing it.
Fig 2. Changes in capacity to fix carbon in ocean and land over five different scenarios.