The subjects of climate and climate change are enormous and embrace many scientific disciplines. This review seeks to deal solely with the scientific evidence and is based heavily on the work of the Intergovernmental Panel on Climate Change (IPCC). The review sifts some of the more important fundamental issues and provides a bibliography for those wishing to take the subject further.
Published March 2017 – Now Archived
There is strong evidence that the Earth’s climate has changed many times since the formation of Earth within the solar system some 4.6 billion years ago. Each change has had major implications on the ability of the Earth to support life of all kinds.
In historic times, say more than a million years ago, the evidence and the reasons for climate change are based upon assessments of a variety of complex phenomenon. Whereas in very recent times, say within the last 200 years, advances in scientific instrumentation and knowledge have thrown more light on the subject. There is much more quantitative evidence available concerning such phenomena as atmospheric temperatures and composition, sea levels, ice quantities in the polar regions, etc., for this latter period.
The questions which attract the headlines and which could influence future life on the planet are:
- whether the observed current trends in climate change are man-made and cumulative and
- if so, whether the changes can be halted or at least slowed significantly.
This Review of Current Knowledge (ROCK) seeks to deal solely with the scientific evidence and is based heavily on the work of the Intergovernmental Panel on Climate Change (IPCC). As an intergovernmental body jointly established in 1988 by the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP), the Intergovernmental Panel on Climate Change has provided policymakers with the most authoritative and objective scientific and technical assessments. A series of IPCC Assessment Reports, Special Reports, Technical Papers, Methodology Reports and other products have been issued by the panel between 1990 and 2013.
The findings of the comprehensive IPCC 2013 report have been broadly accepted by the international community, culminating in the intergovernmental Paris Agreement of 2016. The central aim of the Paris Agreement is to strengthen the global response to the threat of climate change by keeping a global temperature rise this century less than 2.0 deg C above pre-industrial levels and to pursue efforts to limit the temperature increase even further to 1.5 deg C. Additionally, the agreement aims to strengthen the ability of countries to deal with the impacts of climate change. To reach these ambitious goals, appropriate financial flows, a new technology framework and an enhanced capacity-building framework (social or personal development that focuses on understanding the obstacles that inhibit it) will be put in place, thus supporting action by developing countries and the most vulnerable countries, in line with their own national objectives. The Agreement also provides for enhanced transparency of action and support through a more robust framework. The Agreement was signed by 117 Heads of Governments (or their representatives) on 22 April 2016 with an effective date of 4 November 2016.
The subjects of climate and climate change are enormous and embrace many scientific disciplines. There is a huge amount of literature on the subject from scientists around the globe. The IPCC 2013 Report alone runs to more than 1,500 pages. This ROCK sifts some of the more important fundamental issues and provides a bibliography for those wishing to take the subject further.
Chapter 2 gives information on the nature of climate, the factors which cause climate change and the way in which evidence is assembled for investigating historic climate change.
Chapter 3 describes some of the evidence for the historical climate changes which have occurred since the formation of the Earth some 4.6 billion years ago. The earliest climate change events were probably down to astronomical variations during the early development of the solar system.
Chapter 4 describes later times when anthropological and other effects came into play. These have been very noticeable since the start of the industrial revolution around 1800.
Chapter 5 looks more closely at the recent climate changes which are evident in the last 200 years or so.
Chapter 6 describes the potential effects of the current trends in climate change if they were to continue for the foreseeable future. Sophisticated climate models capable of evaluating numerous possible scenarios are used to make these predictions.
Chapter 7 explores how current trends can be reversed based on IPCC recommendations. It describes how the international community has agreed on a way forward and how the UK is to participate in the process.