Steven J. Lade

Finite sampling interval effects in Kramers-Moyal analysis

Abstract Large sampling intervals can affect reconstruction of Kramers–Moyal coefficients from data. A new method, which is direct, non-stochastic and exact up to numerical accuracy, is developed to estimate these finite time effects. The method is applied numerically to biologically inspired examples. Exact finite time effects are also described analytically for two special cases. The approach developed will permit better evaluation of Langevin or Fokker–Planck based models from data with large sampling intervals. It can also be used to predict the sampling intervals for which finite time effects become significant.

Trajectories of the Earth System in the Anthropocene

We explore the risk that self-reinforcing feedbacks could push the Earth System toward a planetary threshold that, if crossed, could prevent stabilization of the climate at intermediate temperature rises and cause continued warming on a “Hothouse Earth” pathway even as human emissions are reduced. Crossing the threshold would lead to a much higher global average temperature than any interglacial in the past 1.2 million years and to sea levels significantly higher than at any time in the Holocene. We examine the evidence that such a threshold might exist and where it might be. If the threshold is crossed, the resulting trajectory would likely cause serious disruptions to ecosystems, society, and economies. Collective human action is required to steer the Earth System away from a potential threshold and stabilize it in a habitable interglacial-like state. Such action entails stewardship of the entire Earth System—biosphere, climate, and societies—and could include decarbonization of the global economy, enhancement of biosphere carbon sinks, behavioral changes, technological innovations, new governance arrangements, and transformed social values.

Resilience offers escape from trapped thinking on poverty alleviation

The complex roles of nature and culture in poverty traps call for diverse and often transformative poverty alleviation strategies. The poverty trap concept strongly influences current research and policy on poverty alleviation. Financial or technological inputs intended to “push” the rural poor out of a poverty trap have had many successes but have also failed unexpectedly with serious ecological and social consequences that can reinforce poverty. Resilience thinking can help to (i) understand how these failures emerge from the complex relationships between humans and the ecosystems on which they depend and (ii) navigate diverse poverty alleviation strategies, such as transformative change, that may instead be required. First, we review commonly observed or assumed social-ecological relationships in rural development contexts, focusing on economic, biophysical, and cultural aspects of poverty. Second, we develop a classification of poverty alleviation strategies using insights from resilience research on social-ecological change. Last, we use these advances to develop stylized, multidimensional poverty trap models. The models show that (i) interventions that ignore nature and culture can reinforce poverty (particularly in agrobiodiverse landscapes), (ii) transformative change can instead open new pathways for poverty alleviation, and (iii) asset inputs may be effective in other contexts (for example, where resource degradation and poverty are tightly interlinked). Our model-based approach and insights offer a systematic way to review the consequences of the causal mechanisms that characterize poverty traps in different agricultural contexts and identify appropriate strategies for rural development challenges.

Generalized modeling of empirical social‐ecological systems

Modeling social-ecological systems is difficult due to the complexity of ecosystems and of individual and collective human behavior. Key components of the social-ecological system are often over-simplified or omitted. Generalized modeling is a dynamical systems approach that can overcome some of these challenges. It can rigorously analyze qualitative system dynamics such as regime shifts despite incomplete knowledge of the models constituent processes. Here, we review generalized modeling and use a recent study on the Baltic Sea cod fisherys boom and collapse to demonstrate its application to modeling the dynamics of empirical social-ecological systems. These empirical applications demand new methods of analysis suited to larger, more complicated generalized models. Generalized modeling is a promising tool for rapidly developing mathematically rigorous, process-based understanding of a social-ecological systems dynamics despite limited knowledge of the system.

The optimal driving waveform for overdamped, adiabatic rocking ratchets

The optimal driving waveform among a wide class of admissible functions for an overdamped, adiabatic rocking ratchet is shown to be dichotomous. ‘Optimum’ is defined as that which achieves the maximum (or minimum negative) average particle velocity. Implications for the design of ratchets, for example in nanotechnological transport, may follow. The main result is applicable to a general class of adiabatic responses. Much scope exists for further studies of ratchet waveform optimization in other regimes.

Opinions of 12 to 13-year-olds in Austria and Australia on the worry, cause and imminence of Climate Change

Although we are in the third decade of climate science communication as a discipline, and there is overwhelming scientific consensus and physical evidence for climate change, the general public continues to wrestle with climate change policy and advocacy. Early adolescence (12 to 13 years old) is a critical but under-researched demographic for the formation of attitudes related to climate change. This paper presents opinions on the worry, cause, and imminence of climate change that were collected from n=463 1st year secondary school students (12-13 years old) in public secondary schools in inner-urban centres in Austria and Australia. Overall, 86.83% of eligible respondents agreed that climate change was probably or definitely something we should worry about, 80.33% agreed that climate change was probably or definitely caused by humans, and 83.17% agreed that climate change was probably or definitely something that was happening now. The respondents’ opinions were also compared to their respective adult population, with Australian 12-13 year olds showing strong positive climate-friendly attitudes, both in comparison to their adult population, and to their Austrian peers. In addition, although the opinions of Austrian 12-13 year olds were quite high, they did not reflect the higher climate-friendly opinions of their adult community. Our results suggest that socio-cultural worldview or socio-cultural cognition theory may not have the influence on this age group as it does on the respective adult population – and, if they are affected, there are attitudes or factors in this age group which resist the opinion-influence from their mature community. These findings are significant as early adolescents may be pivotal in the climate science communication arena and investigating their opinions with regard to climate change may offer an unexplored and under-utilised target for future communication efforts and climate literacy programmes.

When optimization for governing human-environment tipping elements is neither sustainable nor safe

Optimizing economic welfare in environmental governance has been criticized for delivering short-term gains at the expense of long-term environmental degradation. Different from economic optimization, the concepts of sustainability and the more recent safe operating space have been used to derive policies in environmental governance. However, a formal comparison between these three policy paradigms is still missing, leaving policy makers uncertain which paradigm to apply. Here, we develop a better understanding of their interrelationships, using a stylized model of human-environment tipping elements. We find that no paradigm guarantees fulfilling requirements imposed by another paradigm and derive simple heuristics for the conditions under which these trade-offs occur. We show that the absence of such a master paradigm is of special relevance for governing real-world tipping systems such as climate, fisheries, and farming, which may reside in a parameter regime where economic optimization is neither sustainable nor safe.Economic optimization in environmental governance was criticized for delivering short-term gains at the expense of long-term environmental degradation. Here, the authors use a stylized model of human-environment tipping elements to show no paradigm guarantees fulfilling another paradigm.