Change is Afoot

At great risk of starting this blog with the blindingly obvious, water is, without doubt, extremely important. I'm sure this isn't news to anyone. Drinking, washing, cleaning, cooking, cooling, farming, manufacturing, powering - just to name a few - are all familiar things we as humans utilise water for.  However, it is water's importance to us as humans which makes us so vulnerable to changes in the earth's hydrological cycle. This cycle describes the continuous movement of water around the earth, in three different ways - above, on, and below the surface of the earth. Fundamentally, it's a simple as understanding that the sun warms water on the earth, and it evaporates. As it rises, this water cools and condenses, eventually falling as rain. Then that whole cycle repeats itself. Take a look at the diagram below to see for yourself some of the mechanisms involved in this.

Credit: Ehud Tal

Most of us are now familiar with the idea of climate change, it having become a global and highly politicised debate, something that has moved far beyond the realms of 'traditional' scientific debate into something that increasingly resembles political wrangling that we would often associate with less scientific decisions, such as the current debate in the western world on immigration and Islam. Donald Trump suggesting the theory of climate change is a Chinese invention to harm the US economy is probably the best proof I have of this, but I welcome any other suggestions of the most barmy things that have been said about climate change. 

All this 'debate' about climate change means that sometimes it's quite hard to pin down what it actually is. The IPCC (Intergovernmental Panel on Climate Change) define it as:

"A change in the state of the climate that can be identified (e.g. using statistical tests) by changes in the mean and/or the variability of its properties, and that persists for an extended period, typically decades or longer."

That definition is a wordy way of saying that the general patterns of weather are changing. All the scientific evidence points towards the idea that we as humans are driving climate change through our behaviour, most notably the emission of greenhouse gases such as carbon dixoide and methane into the atmosphere, which leads to warming of the earth's temperatures. Cook et al. (2013) suggest through meta-analysis of academic literature that 97% of peer-reviewed papers that discuss the idea of anthropogenic global warming endorse the theory that humans are leading to a rise in the earth's temperature. While some take the opinion that this level of consensus means there is something corrupt about the science (particularly given the fact these papers are reviewed by peers, all members of the supposed group that has a political reason to advance climate change as a theory), I truly believe this level of consensus is because the science is sound and logical.

All of the different processes of the hydrological cycle (shown in the diagram above) have the potential to be affected by climate change: precipitation, evaporation, snowmelt, runoff, infiltration- just to name a few. The IPCC identified a few key trends that are likely to pose a risk to freshwater resources around the world in their Climate Change 2014 report:

• A reduction in surface water and groundwater resources in the tropics.
• Change in flood frequency around the world, with global flood risk generally increasing.
• An increasingly frequency of meteorological drought (less rainfall) and agricultural droughts (less soil moisture) in current dry regions.
• Negative changes to freshwater ecosystems as a result of changes in water flow and quality
• A reduction in raw water quality, posing risks to drinking water quality.
• A less reliable water supply, due to increasing variability of surface water availability, and the increasing groundwater abstraction resulting from this.

In this blog, I'm aiming to explore how these climate change induced changes to the hydrological cycle may/will affect the water on earth that we as humans rely on, and the resultant effects on human livelihoods, well being, and health. I've always had a passion for the study of water, spanning all the way back to school geography lessons - I'm fascinated at how something seemingly so simple as a glass of water, or water flowing in a river, is so incredibly multi-faceted, and how water is ultimately so important to life. I really hope I can bring across that passion in the coming months, and provide a snapshot into why we really need to be concerned about the effects of climate change on the hydrological system as humans. This is also a brilliant opportunity to challenge my own understanding and opinions, as well as finding out other peoples - please do comment if you find something interesting or want to know more!

I'm off for a glass of water.