Climate in the past

Carbon dioxide is the predominant constituent of the current martian atmosphere composing -95% of the -7 mbar of gas present in the atmosphere today. Additionally, CO2 is thought to have played an important role in martian climate in the past, possibly contributing to an early warmer climate due to the greenhouse effect (Fanale et al. 1992). The Viking entry mass spectrometer measured the values of and l O/l O in... 

Fig. 1.6 Two isotopes of oxygen 0 and 0. From the ratio of these isotopes, the climate in the past can be reconstructed...

In the past few years, unstable and extreme weather patterns are increasingly occurring as phenomena of climate change, and the link to greenhouse gas (GHG) emissions is scientifically accepted. From an economic point of view, extreme weather patterns are causing major damage to health, property, and business. 

In the past few years, the insurance industry has developed financial products suitable for dealing with climate change-related risks in the direction to play a role far beyond simply compensating climate change s victims for their losses ex post. The activity of the insurance has become relevant as a political economic instruments within an ex ante strategy to financially manage large-scale catastrophes, as a complement of ex post instruments for the compensation of disaster losses. 

In past times the total mass of stored organic carbon may have been larger or smaller than it is now, depending on the past climate. Let us define as the norm the amount of carbon presently stored, M, and define a time dependent factor, M/M, by which the organic carbon reservoir may be increased (M/M > 1) as in a lush, tropical coal age, or decreased (M/M < 1) as in an ice age, where M is the mass of organic carbon at the time in the past when the material was alive. We assume that the total amount of atmospheric carbon dioxide has always remained the same (which may or may not be true). 

In bog formations extensive quantities of organic matter are stored during glacial periods. These processes could be a critical link in the explanation of large climatic changes that have occurred in the past. 

Fluctuations in the Earth s average annual temperature over long periods are a normal and natural aspect of the planet s climate patterns. There is abundant evidence that at some times in the past the Earth has been much colder than it is now and at other times it has been much warmer. 

In short, ice core and other long-term records show that there have been dramatic climate changes in the past, some of them within or shorter than a typical human life span. Separating out such natural variability from anthropogenic perturbations remains a major challenge, particularly when it is possible that the anthropogenic emissions may act to hasten or jolt the climate system into a relatively rapid transition from one state to another. 

This is more than a matter of academic interest. Faced with the likelihood that human activities such as the burning of fossil fuels have altered the world s climate over the past century, we need to know more about the factors that control climate in order to predict what the future might hold. The study of stable-isotope records of the past has shown that the climate system is vastly more complex than anyone dreamed several decades ago, and that it has a capacity for changing its behaviour rapidly and in ways that are hard to anticipate. 

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