During the Coronavirus Disease 2019 (COVID-19) pandemic, science advisory mechanisms did not always live up to expectations. What practical steps can the expert community take to improve advisory ...mechanisms in an emergency?
This article summarizes the changes in landscape structure because of human land management over the last several centuries, and using observed and modeled data, documents how these changes have ...altered biogeophysical and biogeochemical surface fluxes on the local, mesoscale, and regional scales. Remaining research issues are presented including whether these landscape changes alter large‐scale atmospheric circulation patterns far from where the land use and land cover changes occur. We conclude that existing climate assessments have not yet adequately factored in this climate forcing. For those regions that have undergone intensive human landscape change, or would undergo intensive change in the future, we conclude that the failure to factor in this forcing risks a misalignment of investment in climate mitigation and adaptation. WIREs Clim Change 2011, 2:828–850. doi: 10.1002/wcc.144
This article is categorized under:
Paleoclimates and Current Trends > Climate Forcing
Abstract
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 2005–2050 fossil-fuel-and-industry (FFI) CO
2
emissions growth rates most consistent with observations from 2005 to 2020 and International Energy Agency (IEA) projections to 2050. These scenarios project between 2 °C and 3 °C of warming by 2100, with a median of 2.2 °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 °C or below 2 °C.
The common methodology in dynamical regional climate downscaling employs a continuous integration of a limited‐area model with a single initialization of the atmospheric fields and frequent updates ...of lateral boundary conditions based on general circulation model outputs or reanalysis data sets. This study suggests alternative methods that can be more skillful than the traditional one in obtaining high‐resolution climate information. We use the Weather Research and Forecasting (WRF) model with a grid spacing at 36 km over the conterminous U.S. to dynamically downscale the 1‐degree NCEP Global Final Analysis (FNL). We perform three types of experiments for the entire year of 2000: (1) continuous integrations with a single initialization as usually done, (2) consecutive integrations with frequent re‐initializations, and (3) as (1) but with a 3‐D nudging being applied. The simulations are evaluated in a high temporal scale (6‐hourly) by comparison with the 32‐km NCEP North American Regional Reanalysis (NARR). Compared to NARR, the downscaling simulation using the 3‐D nudging shows the highest skill, and the continuous run produces the lowest skill. While the re‐initialization runs give an intermediate skill, a run with a more frequent (e.g., weekly) re‐initialization outperforms that with the less frequent re‐initialization (e.g., monthly). Dynamical downscaling outperforms bi‐linear interpolation, especially for meteorological fields near the surface over the mountainous regions. The 3‐D nudging generates realistic regional‐scale patterns that are not resolved by simply updating the lateral boundary conditions as done traditionally, therefore significantly improving the accuracy of generating regional climate information.
Land Use and Climate Change Pielke, Roger A.
Science (American Association for the Advancement of Science),
12/2005, Volume:
310, Issue:
5754
Journal Article
Peer reviewed
Change and variability in land use by humans and the resulting alterations in surface features are major but poorly recognized drivers of long-term global climate patterns. Along with the diverse ...influences of aerosols on climate, these spatially heterogeneous land use effects may be at least as important in altering the weather as changes in climate patterns associated with greenhouse gases. On page 1674 of this issue, Feddema et al. report modeling results indicating that future land use and land cover will continue to be an important influence on climate for the next century. One implication of this work is that the Intergovernmental Panel on Climate Change (IPCC), which has yet to appreciate the significance of the full range of phenomena that drive climate change, risks rapidly falling behind the evolving science if this effect is not included. Although the impact of land use and land cover on the atmospheric concentration of carbon dioxide and methane, and on the global average surface albedo, have been included in international climate change assessments, the role of land use and land cover change and variability in altering regional temperatures, precipitation, vegetation, and other climate variables has been mostly ignored.
The rehabilitation of the idea of adaptation is overdue and seems straightforward. But there is an elephant in the room: the core assumptions underlying contemporary climate-change policy conflict ...with the goal of increasing resilience to natural climate change and variability.
Climate science research and assessments under the umbrella of the Intergovernmental Panel on Climate Change (IPCC) have misused scenarios for more than a decade. Symptoms of misuse have included the ...treatment of an unrealistic, extreme scenario as the world’s most likely future in the absence of climate policy and the illogical comparison of climate projections across inconsistent global development trajectories. Reasons why such misuse arose include (a) competing demands for scenarios from users in diverse academic disciplines that ultimately conflated exploratory and policy relevant pathways, (b) the evolving role of the IPCC – which extended its mandate in a way that creates an inter-relationship between literature assessment and literature coordination, (c) unforeseen consequences of employing a temporary approach to scenario development, (d) maintaining research practices that normalize careless use of scenarios, and (e) the inherent complexity and technicality of scenarios in model-based research and in support of policy. Consequently, much of the climate research community is presently off-track from scientific coherence and policy-relevance. Attempts to address scenario misuse within the community have thus far not worked. The result has been the widespread production of myopic or misleading perspectives on future climate change and climate policy. Until reform is implemented, we can expect the production of such perspectives to continue, threatening the overall credibility of the IPCC and associated climate research. However, because many aspects of climate change discourse are contingent on scenarios, there is considerable momentum that will make such a course correction difficult and contested - even as efforts to improve scenarios have informed research that will be included in the IPCC 6th Assessment.
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