scholarly journals Croll, feedback mechanisms, climate change and the future

2021 ◽  
pp. 1-19
Author(s):  
Roy THOMPSON
Keyword(s):  
Climate Change ◽  
Geological Time ◽  
Ice Cap ◽  
Denudation Rates ◽  
Modelling Studies ◽  
Astronomical Theory ◽  
Subject Areas ◽  
Orbital Precession ◽  
Earth’S Climate ◽  
Philosophical Questions

ABSTRACT Our climate future depends on the delicate, fine balance of earth processes first elaborated on by James Croll, born 200 years ago in 1821. A childhood victim of the Scottish clearances, Croll, after following various indifferent occupations, managed to remove to the then rapidly industrialising city of Glasgow and eventually to Scotland's capital, Edinburgh. He blossomed as a most original, outside-the-box, thinker of great intellectual strength and modesty. He carried out scores of studies across a broad range of research topics, many related to the physical causes of climate change. He is well known for his astronomical theory of the ice ages, but should be much better regarded for his incisive physical insights into the central importance of feedbacks in the Earth system. Although humble, Croll was an ardent controversialist who strongly, perhaps over-strongly, always defended his corner. As well as his many accomplishments as a man of science, Croll was committed to exploring philosophical questions of theism and determinism, topics which occupied his earliest and last publications. A ‘top ten’ selection out of the varied subject areas that Croll tackled are explored herein, along with a brisk survey of their legacy to contemporary modelling studies and to Earth's climate future: (1) causes of climate change (1864); (2) ice-cap melt and sea-level rise (1865); (3) predicting future climates using eccentricity (1866); (4) combining orbital precession, eccentricity and obliquity (1867); (5) geological time and the date of the glacial epochs (1868); (6) geological time and denudation rates (1868); (7) ocean currents and the hemispherical temperature difference (1869); (8) feedbacks – a remarkable circumstance which led to changes of climate (1875); (9) temperature of space and its bearing on terrestrial physics (1880); (10) the causes of mild polar climates (1884).

scholarly journals Global warming and other climate change phenomena on the geological time scale

2019 ◽  
Vol 23 (Suppl. 5) ◽  
pp. 1435-1455
Author(s):  
Miodrag Mesarovic
Keyword(s):  
Climate Change ◽  
Global Warming ◽  
Time Scale ◽  
Climate Changes ◽  
Geological Time ◽  
Geological Time Scale ◽  
The Future ◽  
Entire History ◽  
Past Climate Change ◽  
Earth’S Climate

Global warming and other climate change phenomena became a worldwide exploited subject over recent decades. World science has made enormous progress in understanding past climate change and its causes, and continues to study current and potential impacts that will affect people in the future. All scientists agree that the Earth's climate is changing due to natural phenomena, and most of them argue that human activities are increasing the greenhouse effect, while some scientists attribute climate changes exclusively to the natural causes. Though there still is, and always will be, need for multiple lines of research on an extremely complex system like Earth's climate is, an immediate consensus is crucial for decision-makers to place climate change in the context of other large challenges facing the world today. This paper discusses the existing body of evidence on climate changes in the past, and uncertainties that prevent scientists to reach full consensus on how climate might change in the future. It extends the time scale of climate changes over the entire history of Earth to help better understanding of hypothetical changes and their consequences that could be expected both in the near and in a very distant future.

From “Inconvenient Truth” to Effective Governance

2018 ◽  
Author(s):  
Richard Passarelli ◽  
David Michel ◽  
William Durch
Keyword(s):  
Climate Change ◽  
Global Climate ◽  
Climate System ◽  
Global Public Good ◽  
Environmental Groups ◽  
Quarter Century ◽  
Effective Governance ◽  
Political Response ◽  
Earth’S Climate ◽  
National Governments

The Earth’s climate system is a global public good. Maintaining it is a collective action problem. This chapter looks at a quarter-century of efforts to understand and respond to the challenges posed by global climate change and why the collective political response, until very recently, has seemed to lag so far behind our scientific knowledge of the problem. The chapter tracks the efforts of the main global, intergovernmental process for negotiating both useful and politically acceptable responses to climate change, the UN Framework Convention on Climate Change, but also highlights efforts by scientific and environmental groups and, more recently, networks of sub-national governments—especially cities—and of businesses to redefine interests so as to meet the dangers of climate system disruption.

Twelfth Century AD

2017 ◽  
Author(s):  
Lonnie G. Thompson ◽  
Alan L. Kolata
Keyword(s):  
Climate Change ◽  
Southern Oscillation ◽  
Sediment Cores ◽  
Critical Role ◽  
Lake Titicaca ◽  
Independent Evidence ◽  
Tropical Regions ◽  
Ice Cap ◽  
Paleoclimate Records ◽  
Past Climate Change

Climate is a fundamental and independent variable of human existence. Given that 50 percent of the Earth’s surface and much of its population exist between 30oN and 30oS, paleoenvironmental research in the Earth’s tropical regions is vital to our understanding of the world’s current and past climate change. Most of the solar energy that drives the climate system is absorbed in these regions. Paleoclimate records reveal that tropical processes, such as variations in the El Niño-Southern Oscillation (ENSO), have affected the climate over much of the planet. Climatic variations, particularly in precipitation and temperature, play a critical role in the adaptations of agrarian cultures located in zones of environmental sensitivity, such as those of the coastal deserts, highlands, and altiplano of the Andean region. Paleoclimate records from the Quelccaya ice cap (5670 masl) in highland Peru that extend back ~1800 years show good correlation between precipitation and the rise and fall of pre-Hispanic civilizations in western Peru and Bolivia. Sediment cores extracted from Lake Titicaca provide independent evidence of this correspondence with particular reference to the history of the pre-Hispanic Tiwanaku state centered in the Andean altiplano. Here we explore, in particular, the impacts of climate change on the development and ultimate dissolution of this altiplano state.

scholarly journals Water Temperature and Hydrological Modelling in the Context of Environmental Flows and Future Climate Change: Case Study of the Wilmot River (Canada)

Water ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2101
Author(s):  
Christian Charron ◽  
André St-Hilaire ◽  
Taha B.M.J. Ouarda ◽  
Michael R. van den Heuvel
Keyword(s):  
Climate Change ◽  
Water Temperature ◽  
Environmental Flows ◽  
Low Flow ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Water Abstraction ◽  
Surface Water Flow ◽  
Modelling Studies ◽  
Rcp 8.5

Simulation of surface water flow and temperature under a non-stationary, anthropogenically impacted climate is critical for water resource decision makers, especially in the context of environmental flow determination. Two climate change scenarios were employed to predict streamflow and temperature: RCP 8.5, the most pessimistic with regards to climate change, and RCP 4.5, a more optimistic scenario where greenhouse gas emissions peak in 2040. Two periods, 2018–2050 and 2051–2100, were also evaluated. In Canada, a number of modelling studies have shown that many regions will likely be faced with higher winter flow and lower summer flows. The CEQUEAU hydrological and water temperature model was calibrated and validated for the Wilmot River, Canada, using historic data for flow and temperature. Total annual precipitation in the region was found to remain stable under RCP 4.5 and increase over time under RCP 8.5. Median stream flow was expected to increase over present levels in the low flow months of August and September. However, increased climate variability led to higher numbers of periodic extreme low flow events and little change to the frequency of extreme high flow events. The effective increase in water temperature was four-fold greater in winter with an approximate mean difference of 4 °C, while the change was only 1 °C in summer. Overall implications for native coldwater fishes and water abstraction are not severe, except for the potential for more variability, and hence periodic extreme low flow/high temperature events.

Introduction

2015 ◽  
Author(s):  
Joanna D. Haigh ◽  
Peter Cargill
Keyword(s):  
Climate Change ◽  
Magnetic Field ◽  
Human Activity ◽  
The Sun ◽  
The Past ◽  
Key Features ◽  
Composition Structure ◽  
Earth’S Climate ◽  
Fundamental Requirement

This introductory chapter provides an overview of the Earth's climate system—its composition, structure, and circulation—and some of the ways in which these vary naturally with time. It examines the key features of the structure of the Sun, its magnetic field, atmosphere, and its emission of radiation and particles. A comprehension of how the sun affects the Earth is a fundamental requirement for understanding how climate has varied in the past and how it might change in the future. This is particularly important in the context of determining the cause(s) of climate change and understanding natural factors in order to be able to attribute to human activity any past or potential future influence on a range of timescales.

Consequences of Deforestation and Climate Change on Biodiversity

2011 ◽  
pp. 24-51 ◽  
Author(s):  
Roland Cochard
Keyword(s):  
Climate Change ◽  
Species Richness ◽  
Economic Valuation ◽  
Keystone Species ◽  
Forest Degradation ◽  
Habitat Destruction ◽  
Forest Fragments ◽  
Extinction Rates ◽  
Earth’S Climate ◽  
Species Extinctions

Ever since their evolution, forests have been interacting with the Earth’s climate. Species diversity is particularly high in forests of stable moist tropical climates, but patterns of diversity differ among various taxa. Species richness typically implies high ecosystem resilience to ecosystem disturbances; many species are present to fill in newly created niches and facilitate regeneration. Species loss, on the other hand, often entails environmental degradation and erosion of essential ecosystem services. Until now species extinction rates have been highest on tropical islands which are characterized by a high degree of species endemism but comparatively low species richness (and therefore high vulnerability to invasive species). Deforestation and forest degradation in many countries has lead to forest fragmentation with similar effects on increasingly insularized and vulnerable forest habitat patches. If forest fragments are becoming too small to support important keystone species, further extinctions may occur in cascading ways, and the vegetation structure and composition may eventually collapse. Until now relatively few reported cases of species extinctions can be directly attributed to climate change. However, climate change in combination with habitat destruction, degradation, and fragmentation may lead to new waves of species extinctions in the near future as species are set on the move but are unable to reach cooler refuges due to altered, obstructing landscapes. To mitigate the future risks of extinctions as well as climate change, major efforts should be undertaken to protect intact large areas of forests and restore wildlife corridors. Carbon sequestration may be seen as just one of many other environmental services of forest biodiversity that deserve economic valuation as alternatives to conversion to often unsustainable agricultural uses.

Global Climate Change: Real or Myth?

2014 ◽  
Author(s):  
Michael H. Fox
Keyword(s):  
Climate Change ◽  
United Nations ◽  
Greenhouse Gases ◽  
Global Climate Change ◽  
Global Climate ◽  
An Inconvenient Truth ◽  
The World ◽  
The United Nations ◽  
Earth’S Climate ◽  
The One

We, the teeming billions of people on earth, are changing the earth’s climate at an unprecedented rate because we are spewing out greenhouse gases and are heading to a disaster, say most climate scientists. Not so, say the skeptics. We are just experiencing normal variations in earth’s climate and we should all take a big breath, settle down, and worry about something else. Which is it? A national debate has raged for the last several decades about whether anthropogenic (man-made) sources of carbon dioxide (CO2 ) and other so-called “greenhouse gases“ (primarily methane and nitrous oxide) are causing the world to heat up. This phenomenon is usually called “global warming,” but it is more appropriate to call it “global climate change,” since it is not simply an increase in global temperatures but rather more complex changes to the overall climate. Al Gore is a prominent spokesman for the theory that humans are causing an increase in greenhouse gases leading to global climate change. His movie and book, An Inconvenient Truth, gave the message widespread awareness and resulted in a Nobel Peace Prize for him in 2008. However, the message also led to widespread criticism. On the one hand are a few scientists and a large segment of the general American public who believe that there is no connection between increased CO2 in the atmosphere and global climate change, or if there is, it is too expensive to do anything about it, anyway. On the other hand is an overwhelming consensus of climate scientists who have produced enormous numbers of research papers demonstrating that increased CO2 is changing the earth’s climate. The scientific consensus is expressed most clearly in the Fourth Assessment Report in 2007 by the United Nations–sponsored Intergovernmental Panel on Climate Change (IPCC), the fourth in a series of reports since 1990. The IPCC began as a group of scientists meeting in Geneva in November 1988 to discuss global climate issues under the auspices of the World Meteorological Organization and the United Nations Environment Program.

Climate Variability in the Context of Climate Change: El Niño and Other Oscillations

2008 ◽  
Author(s):  
Cynthia Rosenzweig ◽  
Daniel Hillel
Keyword(s):  
Climate Change ◽  
Climate Variability ◽  
North Atlantic ◽  
El Niño ◽  
El Nino ◽  
Global Climate ◽  
Climate System ◽  
The Arctic ◽  
The Pacific ◽  
Earth’S Climate

The climate system envelops our planet, with swirling fluxes of mass, momentum, and energy through air, water, and land. Its processes are partly regular and partly chaotic. The regularity of diurnal and seasonal fluctuations in these processes is well understood. Recently, there has been significant progress in understanding some of the mechanisms that induce deviations from that regularity in many parts of the globe. These mechanisms include a set of combined oceanic–atmospheric phenomena with quasi-regular manifestations. The largest of these is centered in the Pacific Ocean and is known as the El Niño–Southern Oscillation. The term “oscillation” refers to a shifting pattern of atmospheric pressure gradients that has distinct manifestations in its alternating phases. In the Arctic and North Atlantic regions, the occurrence of somewhat analogous but less regular interactions known as the Arctic Oscillation and its offshoot, the North Atlantic Oscillation, are also being studied. These and other major oscillations influence climate patterns in many parts of the globe. Examples of other large-scale interactive ocean–atmosphere– land processes are the Pacific Decadal Oscillation, the Madden-Julian Oscillation, the Pacific/North American pattern, the Tropical Atlantic Variability, the West Pacific pattern, the Quasi-Biennial Oscillation, and the Indian Ocean Dipole. In this chapter we review the earth’s climate system in general, define climate variability, and describe the processes related to ENSO and the other major systems and their interactions. We then consider the possible connections of the major climate variability systems to anthropogenic global climate change. The climate system consists of a series of fluxes and transformations of energy (radiation, sensible and latent heat, and momentum), as well as transports and changes in the state of matter (air, water, solid matter, and biota) as conveyed and influenced by the atmosphere, the ocean, and the land masses. Acting like a giant engine, this dynamic system is driven by the infusion, transformation, and redistribution of energy.

Introduction

2004 ◽  
Author(s):  
Robert A. Berner
Keyword(s):  
Climate Change ◽  
Carbon Dioxide ◽  
Carbon Cycle ◽  
Global Climate ◽  
Geological Time ◽  
Short Term ◽  
Quaternary Period ◽  
Geological Time Scale ◽  
The Earth

The cycle of carbon is essential to the maintenance of life, to climate, and to the composition of the atmosphere and oceans. What is normally thought of as the “carbon cycle” is the transfer of carbon between the atmosphere, the oceans, and life. This is not the subject of interest of this book. To understand this apparently confusing statement, it is necessary to separate the carbon cycle into two cycles: the short-term cycle and the long-term cycle. The “carbon cycle,” as most people understand it, is represented in figure 1.1. Carbon dioxide is taken up via photosynthesis by green plants on the continents or phytoplankton in the ocean. On land carbon is transferred to soils by the dropping of leaves, root growth, and respiration, the death of plants, and the development of soil biota. Land herbivores eat the plants, and carnivores eat the herbivores. In the oceans the phytoplankton are eaten by zooplankton that are in turn eaten by larger and larger organisms. The plants, plankton, and animals respire CO2. Upon death the plants and animals are decomposed by microorganisms with the ultimate production of CO2. Carbon dioxide is exchanged between the oceans and atmosphere, and dissolved organic matter is carried in solution by rivers from soils to the sea. This all constitutes the shortterm carbon cycle. The word “short-term” is used because the characteristic times for transferring carbon between reservoirs range from days to tens of thousands of years. Because the earth is more than four billion years old, this is short on a geological time scale. As the short-term cycle proceeds, concentrations of the two principal atmospheric gases, CO2 and CH4, can change as a result of perturbations of the cycle. Because these two are both greenhouse gases—in other words, they adsorb outgoing infrared radiation from the earth surface—changes in their concentrations can involve global warming and cooling over centuries and many millennia. Such changes have accompanied global climate change over the Quaternary period (past 2 million years), although other factors, such as variations in the receipt of solar radiation due to changes in characteristics of the earth’s orbit, have also contributed to climate change.

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