Human activity is irrefutably the cause of the earth’s rapid and unprecedented warming [1]. Relative to the global mean surface temperature (GMST) between 1850 and 1900, the earth’s surface has warmed by approximately 1 DegC in only 170 years [1].
This is the fastest warming rate observed in over 2000 years [1]. Abnormal changes in global climates and extreme weather events worldwide continue to intensify in frequency and magnitude because of this increase in temperature.
Anthropogenic carbon emissions are the primary cause of the earth’s warming, and thus, the main catalyst for climate change. CO2 is profusely released into the atmosphere through activities such as extracting and burning fossil fuels, land use (deforestation and agriculture), industrial operations, urbanization, and transportation [2]. If these practices continue without remediation, and the current rate of warming persists, the GMST is expected to reach (and likely surpass) 1.5 DegC in the next few decades [3]. This is the temperature threshold that the Paris Agreement and Intergovernmental Panel on Climate Change (IPCC) are trying to avoid, forewarning it to be a potential point of no return.
"the GMST is expected to reach (and likely surpass) 1.5 DegC in the next few decades [3]. This is the temperature threshold that the Paris Agreement and IPCC are trying to avoid, forewarning it to be a potential point of no return. "
In 2015, 196 nations committed to the Paris Agreement with the collective goal of reducing global CO2 emissions [4]. The goal of this accord is to keep the global surface temperature increase beneath 2 DegC compared to pre-industrial levels, with hopes of staying far below that margin and effectively limiting the temperature rise to only 1.5 DegC [4]. If we’re to accomplish this ambitious but still attainable goal, immediate and expeditious reductions in CO2 emissions are required worldwide.
"Achieving net zero involves reducing most, if not all, CO2 emissions globally and offsetting any remaining CO2 emissions once they enter the atmosphere."
The IPCC’s Special Report on Global Warming of 1.5°C explains that to prevent the global surface temperature from surpassing 1.5 DegC, CO2 emissions must decline by “about 45 percent from 2010 levels by 2030, reaching ‘net zero’ around 2050” [5]. Achieving net zero involves reducing most, if not all, CO2 emissions globally and offsetting any remaining CO2 emissions once they enter the atmosphere. This global carbon neutrality would inhibit further warming and contribute to the near-term reversal of some of the effects of climate change.
Failure to Reach Net Zero Will Result in Disastrous Climate Conditions
"Every populated area on earth is currently affected by climate change" [1].
The IPCC’s Summary for Policymakers from their Sixth Assessment Report (AR6 SPM) forecasts several troubling and unnerving climate conditions based on potential future emission trajectories. If we fail to reduce our global CO2 emissions, reach net zero, and restrict the earth’s warming to only 1.5 DegC before 2050, the climate crisis we’re witnessing today is guaranteed to escalate over the next eighty years and beyond [1].
Every populated area on earth is currently affected by climate change [1]. Current global climate disruption includes increased precipitation, extreme weather events (i.e., storm surges, flooding, hurricanes etc.), hot extremes, fires, melting ice sheets and snow, rising sea levels, and warmer oceans [1].
Oceans are one of the largest carbon sinks on earth, absorbing about 25% of all CO2 emissions annually, and accounting for 91% of warming [6, 1]. As the upsurge of cumulative CO2 emissions continues, larger amounts of CO2 will be absorbed by land and ocean carbon sinks; however, if global warming approaches or surpasses 2 DegC, most CO2 emissions will linger in our atmosphere, making it the world’s predominant carbon sink by 2100 [1].
Each gradual increase in the earth’s surface temperature, even by half a degree, is enough to worsen the impact of global warming [1]. The AR6 SPM states that the Arctic is expected to warm at over twice the rate of the GMST and that at least once before 2050, the Arctic will have almost no sea ice in September [1]. This melting of polar ice will lead to an onslaught of hazardous climate conditions.
"Just 1 DegC of warming is predicted to magnify extreme precipitation events by 7% [1]. "
Heatwaves will occur across the globe, causing agricultural and ecological droughts that deplete soil moisture and adversely affect crop production (jeopardizing food supplies that sustain large parts of the world). Sea levels will rise at least 2 to 3m even if the earth warms by only 1.5 DegC (2 to 6m if by 2 DegC, 19 to 22m if by 5 DegC) [1]. Precipitation will intensify globally, along with coastal flooding which often results in vast casualties and can make regions uninhabitable. Just 1 DegC of warming is predicted to magnify extreme precipitation events by 7% [1].
"Elevated sea levels, melted polar ice, and ocean acidification are some of the consequences guaranteed to persist regardless of how quickly we can curb CO2 emissions. Still, we can prevent current conditions from becoming worse by taking the proper climate action now. "
Unfortunately, reducing anthropogenic CO2 emissions will not be enough to reverse all the damage of climate change. Even now, certain effects of global warming are already permanent. Elevated sea levels, melted polar ice, and ocean acidification are some of the consequences guaranteed to persist regardless of how quickly we can curb CO2 emissions. Still, we can prevent current conditions from becoming worse by taking the proper climate action now.
To Achieve Net Zero CO2 Emissions By 2050, Immediate Climate Action Is Required
Achieving net zero requires that everyone (individually, corporately, globally) contribute to eliminating CO2 emissions. Government authorities and industry leaders across the globe are especially responsible for the handling of this climate crisis. They will have to take the requisite actions (investing in renewable energy sources, passing environmental legislation, etc.) to reduce CO2 emissions in all sectors and invest in technology which captures and sequesters the emissions that cannot be mitigated.
"The sectors which emit the largest amounts of CO2 annually include the energy sector, industrial sector, building sector, and transportation sector. "
The sectors which emit the largest amounts of CO2 annually include the energy sector, industrial sector, building sector, and transportation sector. To stay on track with attaining net zero emissions by 2050, the emissions produced by these, and all, sectors must be cut in half by the end of this decade. Through the development of cost-effective and feasibly scalable systems, it is possible to sustainably transform these sectors over the next nine years and beyond.
The future of our planet and forthcoming generations is at stake. Together we can collectively reach net zero emissions, but it will require universal effort and immediate, effective solutions to achieve this goal and begin to alleviate the effects of climate change.
References
1. IPCC, 2021: Summary for Policymakers. In: Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Masson-Delmotte, V., P. Zhai, A. Pirani, S. L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M. I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T. K. Maycock, T. Waterfield, O. Yelekçi, R. Yu and B. Zhou (eds.)]. Cambridge University Press. In Press. https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_SPM_final.pdf
2. Main sources of carbon dioxide emissions [blog]. CO2 Human Emissions; [accessed 2021 Oct 27]. https://www.che-project.eu/news/main-sources-carbon-dioxide-emissions
3. IPCC, 2018: Global Warming of 1.5°C. An IPCC Special Report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty [Masson-Delmotte, V., P. Zhai, H.-O. Pörtner, D. Roberts, J. Skea, P.R. Shukla, A. Pirani, W. Moufouma-Okia, C. Péan, R. Pidcock, S. Connors, J.B.R. Matthews, Y. Chen, X. Zhou, M.I. Gomis, E. Lonnoy, T. Maycock, M. Tignor, and T. Waterfield (eds.)]. In Press. https://www.ipcc.ch/site/assets/uploads/sites/2/2019/06/SR15_Full_Report_High_Res.pdf
4. The Paris Agreement. United Nations Framework Convention on Climate Change; c2021. [accessed 2021 Oct 26]. https://unfccc.int/process-and-meetings/the-paris-agreement/the-paris-agreement
5. Summary for Policymakers of IPCC Special Report on Global Warming of 1.5°C approved by governments. 2018 Oct 8. Incheon, Republic of Korea: The Intergovernmental Panel on Climate Change; [accessed 2021 Oct 26]. https://www.ipcc.ch/2018/10/08/summary-for-policymakers-of-ipcc-special-report-on-global-warming-of-1-5c-approved-by-governments/
6. Shutler J, Watson A. Guest post: The oceans are absorbing more carbon than previously thought [blog] Carbon Brief. [accessed 2021 Oct 27]. https://www.carbonbrief.org/guest-post-the-oceans-are-absorbing-more-carbon-than-previously-thought
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