Although we hear about it almost daily, how many of us really understand the nature of climate and how it functions?
Because it effects us all and the choices that we make effect it, then we all need to have a far greater understanding of what regulates climate and how it relates to our day-to-day lives. This would be much more productive than trying to adapt to the increasingly extreme weather conditions or waiting for governments to eventually make decisions that consider the long-term good of the many. An important point that is often missed out of climate change discussions is the fact that the water cycle and climate cycle are not two separate systems.
“The water cycle plays a key role in the maintenance of the climate system as a moderator of the Earth’s energy cycle. It is through the water cycle that incoming solar energy is redistributed through the Earth system via the atmosphere and oceans.” – Download: USGCRP, Draft White Paper, Chapter 7, ‘The Global Water Cycle and its Role in Climate and Global Change’, 2002.Pdf
This may seem simple but unless climate and the water cycle are put in their right context side by side, efforts to address either water or climate problems will be seriously undermined.
The global water cycle and climate change need to be addressed together, recognising that anything that impacts upon the water cycle, also impacts upon climate and vice versa. For example – mass deforestation sets off a chain of reactions that destabilise the water cycle, which then have knock on effects upon climate systems. These effects can range from cyclones and hurricanes, to flooding and drought. Generally these alarming repercussions are looked at in isolation but it is only really by looking at the entire water cycle and climate system collectively that cohesive solutions can be applied.
“While attention thus far has focused on the impact of climate changes on the water cycle, the altered paradigm recommends concentrating attention on the impact of changes in the water cycle on climate changes.” Download: M. Kravcík et al. Water for the Recovery of the Climate – A New Water Paradigm, 2007.pdf
Up until recently the concept of climate included the global water cycle in its three phases of liquid, solid and gas. It was clearly understood that it was changes in this cycle, which were altering climate and the US Global Change Research Program, involving NASA was initiated in the 1990’s to gain greater understanding of the processes involved. In September 1999, as an essential element of this multi billion-dollar program, a water cycle study was initiated. This was with the aim of determining whether human induced changes were affecting the intensification of the water cycle and how this affected climate. One of their conclusions was that changes in land cover and land use can have significant, even drastic, impacts on the water cycle at local and regional scales. Seeing that massive deforestation programs have been happening globally, these impacts are also at international scales.
“The hydrological cycle is the life-blood of many of the organisms that inhabit the Earth. At the same time it is, in many ways, the engine of the climate system. Human activities are now influencing the cycle at the global scale.” Download: W. Steffen et al. , ‘Global Change and the Earth System A Planet Under Pressure’, 2004.Pdf
More attention needs to be given to the significant effects that water vapour greenhouse gas has in the atmosphere.
“Water vapour in the atmosphere acts as a powerful greenhouse gas and nearly doubles the effects of greenhouse warming caused by carbon dioxide, methane and all similar gases.” Download: Moustaffa T Chahine, ‘The hydrological cycle and its influence on climate’, 1992.pdf
Increased quantities of greenhouse gases in the upper atmosphere are widely recognised to be a major cause of the amplification of climate change. However water vapour is not often mentioned. This seems to be a great oversight because water vapour is the most abundant greenhouse gas in the atmosphere. According to studies it accounts for approximately 60% of the greenhouse effect. Whereas Carbon Dioxide accounts for approximately 26%. Therefore as the global water cycle becomes destabilised and there are larger quantities of water vapour in the atmosphere, it has a direct feedback effect on climate.
“For many, the term ‘climate’ refers to long-term weather statistics. However, more broadly and more accurately, the definition of climate is a system consisting of the atmosphere, hydrosphere, lithosphere, and biosphere. Physical, chemical and biological processes are involved in interactions among the components of the climate system. Vegetation, soil moisture, and glaciers, for example, are as much a part of the climate system as are temperature and precipitation.” Download: Pielke. R. Sr, A broader view of the role of humans in the climate system, 2008.pdf
“The climate system is a complex, interactive system consisting of the atmosphere, land surface, snow and ice, oceans and other bodies of water, and living things.” Download: IPPC. Historical Overview of Climate Change Science, 2001.pdf