Potsdam Institute for Climate Impact Research

About: Potsdam Institute for Climate Impact Research is a facility organization based out in Potsdam, Germany. It is known for research contribution in the topics: Climate change & Global warming. The organization has 1519 authors who have published 5098 publications receiving 367023 citations.

Influence of Southern Hemisphere Winds on North Atlantic Deep Water Flow

Abstract: A series of experiments with a hybrid model (ocean circulation model with simple atmospheric feedback model) and an ocean-only model is used to study the sensitivity of the ocean’s deep overturning circulation to Southern Hemisphere winds. In particular, the “Drake Passage effect” is examined. The results show that two factors weaken the control that the Drake Passage effect exerts over the flow of North Atlantic Deep Water (NADW). The first is that thermohaline forcing alone can generate about 75% of the NADW flow found in our model; this ability is lost if atmospheric feedback is neglected. The second is that about two-thirds of the downwelling induced by Ekman transport across Drake Passage occurs in the Southern Hemisphere just north of Drake Passage; only one-third occurs in the North Atlantic and enhances NADW flow. For these two reasons, the influence of Southern Ocean winds on NADW flow is only moderate and not as strong as previously suggested. However, the authors find that the formatio...

Multi-gas emission envelopes to meet greenhouse gas concentration targets: Costs versus certainty of limiting temperature increase

Abstract: This paper presents a set of technically feasible multi-gas emission pathways (envelopes) for stabilising greenhouse gas concentration at 450, 550 and 650 ppm CO2-equivalent and their trade-offs between direct abatement costs and probabilities to meet temperature targets. There are different pathways within the envelope. Delayed response pathways initially follow the upper boundary of the emission envelope and reduce more by the end of the century. In contrast, early action pathways first follow the lower boundary and then the upper boundary. The latter require an early peak in the global emissions but keeps the option open for shifting to lower concentration targets in the future. Costs evaluations depend on the discount rate. Early action profiles have high costs early on, but learning-by-doing and smoother reduction rates over time lead to in most cases to lower costs across the century (net present value (NPV)). To achieve the 450 ppm CO2-equivalent, the global emissions need to peak before 2020. The NPV of costs increase from 0.2% of cumulative gross domestic product to 1.0% as the shift is made from 650 to 450 ppm (discount rate 5%). However, the chances of limiting global mean warming to 21C above pre-industrial levels are very small for peaking and stabilisation at 650 ppm (1–23%) and 550 ppm (1–48%), but increase for a peaking at 510 ppm with subsequent stabilisation 450 ppm to 14–67%. r 2006 Elsevier Ltd. All rights reserved.

Climate economics support for the UN climate targets

Abstract: Under the UN Paris Agreement, countries committed to limiting global warming to well below 2 °C and to actively pursue a 1.5 °C limit. Yet, according to the 2018 Economics Nobel laureate William Nordhaus, these targets are economically suboptimal or unattainable and the world community should aim for 3.5 °C in 2100 instead. Here, we show that the UN climate targets may be optimal even in the Dynamic Integrated Climate–Economy (DICE) integrated assessment model, when appropriately updated. Changes to DICE include more accurate calibration of the carbon cycle and energy balance model, and updated climate damage estimates. To determine economically ‘optimal’ climate policy paths, we use the range of expert views on the ethics of intergenerational welfare. When updates from climate science and economics are considered jointly, we find that around three-quarters (or one-third) of expert views on intergenerational welfare translate into economically optimal climate policy paths that are consistent with the 2 °C (or 1.5 °C) target. The economic optimality of limiting global warming to below 2 °C has been questioned. This analysis shows that the 2 °C target is economically optimal in a version of the DICE model that includes updated climate science, climate damage estimates and evidence on social discount rates.

Evaluating integrated assessment models of global climate change

Abstract: Integrated Assessment Models of global climate change (IAMs) are an established tool to study interlinkages between the human and the natural system. Insights from these complex models are widely used to advise policy-makers and to inform the general public. But up to now there has been little understanding of how these models can be evaluated and community-wide standards are missing. To answer this urgent question is a challenge because the systems are open and their future behavior is fundamentally unknown. In this paper, we discuss ways to overcome these problems. Reflecting on experience from other modeling communities, we develop an evaluation framework for IAM of global climate change. It builds on a systematic and transparent step-by-step demonstration of a model's usefulness testing the plausibility of its behavior. Steps in the evaluation hierarchy are: setting up an evaluation framework, evaluation of the conceptual model, code verification and documentation, model evaluation, uncertainty and sensitivity analysis, documentation of the evaluation process, and communication with stakeholders. An important element in evaluating IAM of global climate change is the use of stylized behavior patterns derived from historical observation. The discussion of two examples is offered in this paper.