By definition, climate change is a long-term shift in weather conditions that is identified by changes in temperature, precipitation, winds, and other indicators which can involve both changes in average conditions and changes in variability, including, for example, extreme events. The physical climate system involves the atmosphere, land surfaces, and oceans of the Earth, along with the snow and ice that is so prominent in many northern climes. These components interact with one another and with aspects of the biosphere of the Earth biosphere to determine not only the day-to-day weather, but also the long-term averages that are referred to as climate.

The most general definition of climate change is a change in the statistical properties of the climate system when considered over long periods of time, regardless of cause. Accordingly, fluctuations over periods shorter than a few decades, such as El Niño, do not represent climate change. The term sometimes is used to refer to climate change caused by human activity, as opposed to changes in climate that may have resulted as part of the natural processes of the Earth. In this sense, especially in the context of environmental policy, the term climate change has unfortunately and incorrectly been associated with anthropogenic (human activities) global warming as the causative factor. Within scientific journals, global warming refers to an increase in the surface temperature of the Earth while climate change is an all-inclusive term that includes global events.

The issue of global climate change is often associated with the use of fossil fuels as sources of energy. Of most concern is the increase in emissions of carbon dioxide (CO₂) due to emissions from fossil fuel combustion. Other factors, including land use, ozone depletion, animal agriculture, and deforestation, are also of concern in the roles they play – both separately and collectively – in affecting climate, microclimate, and various climate variables.

Climate change is inevitable. Or is it? How do we know? And to what extent? It is already happening as a result of the current interglacial period. Contributing to this change are (i) natural effects, which include the Earth in an interglacial period and (ii) anthropogenic effects, which include the release of non-indigenous gases into the atmospheres. However, the exact contribution of each to global climate change is unknown, and the cause can only be partially attributed to interglacial period and somewhat less on anthropogenic effects.

Evidence for a significant change in the climate is substantial, since reasonably complete global records of surface temperature are available beginning from the mid- to late 19^th century – the time period after the Little Ice Age when warming was occurring. But – and perhaps more interestingly – the specific reasons for this change or the nature of it are not fully understood. In the late decades of the 20^th century, the term global warming was in vogue and substantial government funding was available for research in this area. During those decades, the cause of global cooling diminished. However, the term global warming did not fit the prevalent weather patterns either and the preferred term now is global climate change – a more convenient umbrella-like catch-all for any changes (warming or cooling) that are the result of cyclic weather patterns.

In reality, the climate of the Earth can be affected by natural factors that are external to the climate system, such as changes in volcanic activity, solar output, and the variance of the orbit of the Earth around the Sun. Of these, the two factors relevant on timescales of contemporary climate change are changes in volcanic activity and changes in solar radiation. In terms of the energy balance of the Earth, these factors primarily influence the amount of incoming energy. Volcanic eruptions are episodic and have relatively short-term effects on climate.

Moreover, there are indications of a Medieval Warming Period in which the climate was warm, or warmer than it is currently. Such a statement is more than a mere scientific curiosity and has wide significance. It is generally believed that the causative agent of the global climate change is the increased amounts of carbon dioxide in the atmosphere as compared to hundreds of years ago. The carbon dioxide is produced through the combustion of fossil fuels, and the amount in the atmosphere of times past has been deduced by determination of the amounts if carbon dioxide in ice cores. But salient facts related to the mobility of carbon dioxide in ice and snow are ignored. In addition, the temperatures of the Earth during the Medieval Warm Period could not have been due to fossil fuel consumption, and therefore it is more than likely that this demonstrates that warming of the Earth that was initiated during the last century may have been just another natural fluctuation.

A crucial feature of the climate system is that the energy of the Sun is not distributed uniformly, but rather is most intense at the equator and weakest at the poles. This non-uniform energy distribution leads to temperature differences, which the atmosphere and ocean act to reduce by transporting heat from the warm tropics to the cold polar regions. This non-uniform heating and the resulting heat transport give rise to ocean currents, atmospheric circulation, evaporation, and precipitation that are ultimately experienced as weather.

Since there is little or nothing that can be done to deter climate change because of the current interglacial period, in which warming will occur, and because there is currently no major alternative to fossil fuels, politicians and other leaders, who clearly know better, feel compelled to deny it. For exactly the same reasons politicians do not acknowledge the need for preparing for peak energy – perhaps it is too far into the future – that peak energy will occur, and for many politicians looking to the future means looking to the time of the next election.

Currently, in the context of climate change, there needs to be a lesser reliance on emotion and more reliance on hard, accurate and reliably unbiased science. On the other hand, publicly singling out specific researchers on any side of the discussion based on perspectives that they have expressed sends a very dangerous message to all researchers.

Climate change is more a natural hazard and arises as part of the evolution of the Earth; the idea that there can be a one-size-fits-all global solution to address future climate change fails to deal with the real and major issue of climate and climate-related issues. There should be planning (rather than responding to the panic-laden issue related to carbon dioxide) as to the means by which future generations will deal with the effects of an interglacial period on the Earth. There is a need to uphold the principles of fair-minded examination of the evidence and allow open debate.

In spite of the emphasis on increased amounts of carbon dioxide in the atmosphere being the cause of climate change, there are several other factors that can influence the climate which have been largely ignored in favor of the carbon dioxide theory. Moreover, it is the recognition of these events that will eventually stabilize global climate change which can be widely applied to reorient policies and scientific strategies for various countries. In fact, the current information for global climate change points to global warming/climate change being influenced by the sum of all effects with no one effect (such as the anthropogenic effect) being the major contributor from a multi-component group of effects.

It must never be forgotten or ignored that the Earth is constantly changing and has been since its formation; it has gone through different eras like glaciations, among others. However, these changes need thousands of years to be made visible, and the current increase in the average temperature of the Earth since the preindustrial period is happening – provided that the measurements of past climatic temperatures are accurate and beyond reproach. Thus, the assessment that the warming trend that has occurred (somewhat erratically) over the past 100 years is very likely to have some origins in natural events – the precise contributions of natural effects and anthropogenic effects on the climate is not known, but it is more accurate to conclude that many factors continue to influence climate and whether or not human activities have become a dominant force, and are responsible for most of the warming observed, is still very much open to question.

When studying the climate system of the Earth, an area of common confusion relates to whether climate scientists agree or disagree as to whether or not climate change is happening, or, if it is happening, whether or not humans are the primary cause. There are a variety of reasons for this, but (supposedly) a majority of scientists who study climate and publish in peer-reviewed journals agree that human activity is causing the warming of the Earth. But when anthropogenic activities are cited as the main cause of the warming there is serious concern because of the other factors that are often ignored.

To combat the emotion of the moment and future emotions, it is necessary to gather opinions from independent, nongovernment organizations and scientists who are free of financial and political conflicts of interest – too often ideological or economic agendas limit the options. Climate change, whether anthropogenic in its origin or not, is a global phenomenon but it must be recognized that anthropogenic causes of climate change are only one small part of a much wider climate hazard – the dangerous natural weather and climatic events that Mother Nature periodically invokes will always be present.

It is not the purpose of this book to debunk the idea of climate change but to recognize the other (non-human, non-anthropogenic) factors that can play a role in the changing climate and to suggest that there should be more focus on these natural effects as the causative agents of climate change.