Plausible 2005-2050 emissions scenarios project between 2 degrees C and 3 degrees C of warming by 2100

Emissions scenarios used by the Intergovernmental Panel on Climate Change (IPCC) are central to climate change research and policy. Here, we identify subsets of scenarios of the IPCC's 5th (AR5) and forthcoming 6th (AR6) Assessment Reports, including the Shared Socioeconomic Pathway scenarios, that project 2005&ndash;2050 fossil-fuel-and-industry (FFI) CO2 emissions growth rates most consistent with observations from 2005 to 2020 and International Energy Agency (IEA) projections to 2050. These scenarios project between 2 &deg;C and 3 &deg;C of warming by 2100, with a median of 2.2 &deg;C. The subset of plausible IPCC scenarios does not represent all possible trajectories of future emissions and warming. Collectively, they project continued mitigation progress and suggest the world is presently on a lower emissions trajectory than is often assumed. However, these scenarios also indicate that the world is still off track from limiting 21st-century warming to 1.5 &deg;C or below 2 &deg;C. &nbsp;</p

IPCC baseline scenarios have over-projected CO2 emissions and economic growth

Scenarios used by the Intergovernmental Panel on Climate Change (IPCC) are central to climate science and policy. Recent studies find that observed trends and International Energy Agency (IEA) projections of global CO2 emissions have diverged from emission scenario outlooks widely employed in climate research. Here, we quantify the bases for this divergence, focusing on Kaya Identity factors: population, per-capita gross domestic product (GDP), energy intensity (energy consumption/GDP), and carbon intensity (CO2 emissions/energy consumption). We compare 2005&ndash;2017 observations and IEA projections to 2040 of these variables, to 'baseline' scenario projections from the IPCC's Fifth Assessment Report (AR5), and from the shared socioeconomic pathways (SSPs) used in the upcoming Sixth Assessment Report (AR6). We find that the historical divergence of observed CO2 emissions from baseline scenario projections can be explained largely by slower-than-projected per-capita GDP growth&mdash;predating the COVID-19 crisis. We also find carbon intensity divergence from baselines in IEA's projections to 2040. IEA projects less coal energy expansion than the baseline scenarios, with divergence expected to continue to 2100. Future economic growth is uncertain, but we show that past divergence from observations makes it unlikely that per-capita GDP growth will catch up to baselines before mid-century. Some experts hypothesize high enough economic growth rates to allow per-capita GDP growth to catch up to or exceed baseline scenarios by 2100. However, we argue that this magnitude of catch-up may be unlikely, in light of: headwinds such as aging and debt, the likelihood of unanticipated economic crises, the fact that past economic forecasts have tended to over-project, the aftermath of the current pandemic, and economic impacts of climate change unaccounted-for in the baseline scenarios. Our analyses inform the rapidly evolving discussions on climate and development futures, and on uses of scenarios in climate science and policy. </div

What Should Scientists Do When Science Gets Political?

The annual lecture of the Phillips/C. J. “Pete” Silas Program in Ethics and Leadership was presented on October 18, 2017 from 3:00 p.m.- 4:00 p.m. in the College of Computing, Room 016, Georgia Tech.Roger Pielke, Jr. is with the University of Colorado since 2001. Roger’s research focuses on science, innovation and politics.Runtime: 67:12 minutesFracking, climate change, GMOs. These are examples of scientific and technological issues that have become highly polarizing in contemporary American politics. This sets up a challenging situation for scientists and other experts. On the one hand, political conflict is the lifeblood of democratic governance. But on the other hand, political conflict can compromise effective policy making that relies on technical expertise. What roles might experts play in issues that are hyper-politicized? In this talk I’ll draw on research on science in politics as well as my own personal experiences to offer scientists some constructive alternatives for participating effectively in modern democracy while avoiding the pitfalls of politicization

VIDEO: Session 3: Adaptation and Energy Justice

VIDEO: 2:00 p.m. - 3:00 p.m. Conceptual Underpinnings, Session 3: Adaptation & Energy Justice Chair: Alessandro Gomez, Professor of Mechanical Engineering, Yale University and Director, Yale Center for Combustion Studies Speaker: Dr. Mickey Glantz, Director, Consortium for Capacity Building, University of Colorado at Boulder Speaker: Dr. Roger Pielke, Jr., Professor of Environmental Studies, University of Colorado at Boulder; Fellow, Cooperative Institute for Research in Environmental Sciences (CIRES

From Green Revolution to Green Evolution: A Critique of the Political Myth of Averted Famine

This paper critiques the so-called "Green Revolution" as a political myth of averted famine. A "political myth," among other functions, reflects a narrative structure that characterizes understandings of causality between policy action and outcome. As such, the details of a particular political myth elevate certain policy options (and families of policy options) over others. One important narrative strand of the political myths of the Green Revolution is a story of averted famine: in the 1950s and 1960s, scientists predicted a global crisis to emerge in the 1970s and beyond, created by a rapidly growing global population that would cause global famine as food supplies would not keep up with demand. The narrative posits that an intense period of technological innovation in agricultural productivity led to increasing crop yields which led to more food being produced, and the predicted crisis thus being averted. The fact that the world did not experience a global famine in the 1970s is cited as evidence in support of the narrative. Political myths need not necessarily be supported by evidence, but to the extent that they shape understandings of cause and effect in policymaking, political myths which are not grounded in evidence risk misleading policymakers and the public. We argue a political myth of the Green Revolution focused on averted famine is not well grounded in evidence and thus has potential to mislead to the extent it guides thinking and action related to technological innovation. We recommend an alternative narrative: The Green Evolution, in which sustainable improvements in agricultural productivity did not necessarily avert a global famine, but nonetheless profoundly shaped the modern world. More broadly, we argue that one of the key functions of the practice of technology assessment is to critique and to help create the political myths that preserve an evidence-grounded basis for connecting the cause and effect of policy action and practical outcomes.Funding Agencies|Linkoping University</p