Regulation has been given an unfairly bad name. As a top physicist who became an Energy Secretary and took an interest in fridges found out, the right regulation can do the opposite of what economists expect: accelerate innovation and cut costs, as well as cutting emissions.

At any moment in time, you can ride a bike with least effort by cycling in first gear. But if you want to ride around the block with least effort, first gear will not be ideal. By failing to distinguish between these two different situations, economists have recommended the worst possible climate change policy to governments. Contrary to their belief, emissions trading will achieve decarbonisation at maximum cost, and minimum speed.

Important parts of the Earth’s climate and environment can change in ways that are self-reinforcing, sudden, and irreversible. The risks of such changes are under-researched, under-reported in what is communicated by scientists to governments, and underestimated. In the most authoritative science assessments, the most important policy question of all – whether the climate will be stable at low degrees of warming – is hardly even raised.

The greatest progress so far in decarbonising the global economy has been made by governments that ignored the advice of economists. Investing in new technologies turns out to be a more effective way of changing things than taxing the incumbents. We need to stop being surprised by this and start replicating those successes.

We know that the Earth’s climate has changed in the past, including times when humans had yet to put in an appearance. These changes must, therefore, have been the result of ’natural processes’. So how do we know that current changes are not similarly natural? The challenge this poses for science is to understand the processes that were at work in the past, and compare them with the climate drivers, both natural and anthropogenic, at work today. There are two reasons to try to unravel the climatic history of our planet. The first might be described as its intrinsic interest. The more important reason is to see what lessons we can learn that might help us think about potential future climate change, and especially the much slower response of sea level to changes in temperature. This is the reason that it is now an important component of the IPCC process.

At any moment in time, you can ride a bike with least effort by cycling in first gear. But if you want to ride around the block with least effort, first gear will not be ideal. By failing to distinguish between these two different situations, economists have recommended the worst possible climate change policy to governments. Contrary to their belief, emissions trading will achieve decarbonisation at maximum cost, and minimum speed.

Regulation has been given an unfairly bad name. As a top physicist who became an Energy Secretary and took an interest in fridges found out, the right regulation can do the opposite of what economists expect: accelerate innovation and cut costs, as well as cutting emissions.

The greatest progress so far in decarbonising the global economy has been made by governments that ignored the advice of economists. Investing in new technologies turns out to be a more effective way of changing things than taxing the incumbents. We need to stop being surprised by this and start replicating those successes.

Important parts of the Earth’s climate and environment can change in ways that are self-reinforcing, sudden, and irreversible. The risks of such changes are under-researched, under-reported in what is communicated by scientists to governments, and underestimated. In the most authoritative science assessments, the most important policy question of all – whether the climate will be stable at low degrees of warming – is hardly even raised.

A distinct branch of socio-environmental research, grounded in the physical principles of conservation of mass and energy, applies a systems modeling approach to society–environment interactions, emphasizing material and energy flows. Technology and technological advancement, alongside population and resources, feature prominently in determining the metabolisms linking society and nature. This approach mostly focuses on analyzing industrial systems (e.g. Ayers and Kneese, Meadows et al., Beck, Graedel et al.) but also offers insight on agrarian societies (Boserup) and hunter-gatherer communities (Fischer–Kowalski). Across these levels of social organization, technology is variously viewed as overcoming the limits nature places on society, as facilitating the resource exploitation and production of waste that lead to social collapse, or as the basis for internalizing externalities and building a circular economy. Key readings constituting this branch of socio-environmental research draw on tools from economics and engineering, such as input–output models, system models, feedback loops, environmental impact analysis, and material and energy flow accounting.

Chapter 9 is devoted to one of the most important new developments in soil research in the last 50 years: the linkage of geomorphological models with soils on hillslopes. Soils on hillslopes are dynamic entities that are constantly in motion and that exhibit aspects of complex systems, with feedbacks that stabilize them and help ensure their presence on all but the more extreme conditions on Earth. The processes (and models) to describe hillslope mass balance (erosion and production) are introduced. The importance of hillslope erosion and soil production to biogeochemistry is considered. Finally, soils on depositional landforms, which receive the material from the hillslopes, are also considered.

When the mass balance on a glacier changes, the glacier is prone to either advance or retreat. A number of feedback processes can amplify or suppress the reaction. During the Pleistocene, ice sheets fluctuated in phase with the concentration of greenhouse gases in the atmosphere, but which forced the other is uncertain. Changes in mass balance result in a stable response in accumulation areas and an unstable response in ablation areas. In the latter, stability is restored by the arrival of a kinematic wave from the vicinity of the equilibrium line. Kinematic waves on glaciers move as several times the speed of the ice as a whole, and are subtle in topographic expression. For small perturbations, the response time of a glacier to a perturbation in mass balance can be estimated by dividing the maximum thickness of the glacier by the balance rate at the terminus. This estimate can be improved by taking into consideration the lag between the time the perturbation is felt in the accumulation area and the time necessary to transmit that signal to the terminus.