29
B. Anthropogenic Dimension of Climate Change
The scientific community has long achieved a consensus that climate change is induced by
human activity.
In the past, scientific uncertainty, as communicated in scientific research such as the
IPCC assessment reports,126 were used to sow doubt and confusion in public perception
on how much of climate change is attributable to anthropogenic or human activities.127
However,in 2021-2022,the IPCC released its latest reports,the SixthAssessment Reports (AR6),
stating that it is unequivocal that the climate change that is currently being experienced
is anthropogenic in origin, foregoing the use of their previous method of communicating
uncertainty. Human influence has warmed the climate, atmosphere, ocean and land
at a rate that is unprecedented in the last 2000 years.128 The report of Working Group I of
AR6 states that global atmospheric concentrations of the GHG responsible for warming,
such as CO2, methane (CH4), and nitrous oxide (N2O), have all risen significantly in the
last few thousand years.129 In particular, atmospheric CO2 concentrations are higher than
at any time in at least two million years, and concentrations of CH4 and N2O are higher than
at any time in at least 800,000 years.130 These increases in GHG concentrations have been
unequivocally caused by human activities since around 1750.131
126
The IPCC Fifth Assessment Report [AR5] relied on two (2) metrics for communicating the degree of
certainty in key findings: a) confidence in the validity of a finding based on the type, amount, quality
and consistency of evidence, and the degree of agreement; and b) quantified measures of certainty
in a finding expressed probabilistically. The following terms are used to describe the available
evidence: limited, medium or robust; and for the degree of agreement: low, medium or high. A level
of confidence is expressed using five (5) qualifiers: very low, low, medium, high and very high. If
uncertainties can be quantified probabilistically, the following terms are used to indicate the assessed
likelihood: virtually certain (99-100% probability), extremely likely (95-100% probability), very likely
(90-100% probability), likely (66-100% probability), more likely than not (>50-100% probability), about
as likely as not (33-66% probability), unlikely (0-33% probability), very unlikely (0-10% probability),
extremely unlikely (0-5% probability), and exceptionally unlikely (0-1% probability) (citing IPCC, 2013:
Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth
Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)].
Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, p. 36).
127
Kyun Soo Kim, Public Understanding of the Politics of Global Warming in the News Media: The
Hostile Media Approach, 20 Public Underst Sci. 690-705, doi:10.1177/0963662510372313
(2011) & Aaron M. McCright & Riley E. Dunlap, Anti-reflexivity: The American Conservative
Movement’s Success in Undermining Climate Science and Policy, 27 Theory Cult. Soc 100-133,
doi:10.1177/0263276409356001 (2010).
128
IPCC, AR 6, WG1, SPM, supra note 107.
129
Id.
130
Id.
131
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