A Beginners Guide to Climate Change

Before I embark on my journey of trying to determine whether geoengineering or renewable energy provide a resolution to global environmental problems I thought that firstly it would be nice to give you a brief history of environmental change, the causes of it and the resulting situation that we are faced with today. So, here is my 'Beginners Guide to Climate Change'. 

History

The interactions between humans and the environment go beyond that of modern human existence to the time of our hominoid ancestors. In their hunt for food, our ancestors became more knowledgeable about their surrounding environments, they discovered how to manipulate fire and became better at hunting. This allowed them to switch their diet from a vegetarian to an omnivorous one. This new, protein based diet meant the brain size of humans grew threefold enabling them to begin developing stone technologies and ultimately the power to change the Earth. Although our ancestors did not ever fully transform an ecosystem, the progression of humankind begun with them, continuing to eventually culminate with the Industrial Revolution - a Revolution wherein humans became able to influence the environment (Steffen et al, 2011). 

                                                      Source: Youtube - Dr. Rick Potts

The Industrial Revolution has its origins in 18^th Century Britain and 19^th Century Western civilization.  The discovery and subsequent exploitation of fossil fuels replaced agriculture as the most dominant human activity. Humanity was able to undertake new activities with these new fuel sources and existing activities expanded (Steffen et al. 2011).  Populations and economic production grew, more land was transformed for human activity and there was a rise of greenhouse gases –CH4 and nitrous oxide (N2O) and in particular CO2. Consequently, mankind left a significant imprint on the environment.

Further to this, after World War II, human enterprise switched gears, stepping up activity to such an extent that the period of 1945-2000 is known as the Great Acceleration (Hibbard et al, 2006). Trade was made open and capital flows were encouraged in the neoliberal post-World War II economy leading to a spike in the growth levels of all industries. 

Source: Steffen et al., 2011

The emergence of global environmental problems were ignored and growth continued into the twenty first century with the rapid development trajectories in China, India Brazil, South Africa and Indonesia further contributing to the impact of humans on the Earth System (Steffan et al.,2011).

The relationship between humans and the environment changed significantly as they began to alter most of the Earth’s systems; its atmosphere, hydrosphere, biosphere and lithosphere (Zalasiewicz et al, 2011). Consequently, it is asserted that these anthropogenic driven changes provide evidence that humans have altered the Earth system to such an extent that we have entered a new geological epoch: the Anthropocene (Ellis, 2011). The concept of the Anthropocene therefore suggests that the Earth is moving out of its current epoch of the Holocene and that humans are responsible for this due to them having become a ‘geological force in [their] own right’ (Steffen et al.2011). 

Where Does This Leave Us Now?

The continued change inflicted upon the Earth by humans has caused a lot of damage to the Earth system, some of which is irreversible. The Fifth Assessment Report by the Intergovernmental Panel and Climate Change (2013) provides us with the most up to date account of the current state of the Earth system. 

The IPCC report asserts that:

'Warming of the climate system is unequivocal, and since the 1950s, many of the observed

changes are unprecedented over decades to millennia. The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, sea level has risen, and the concentrations of greenhouse gases have increased' (IPCC, 2013). 

Anthropogenic climate change is now beyond dispute. Human influence on the climate system is evident in the increased atmospheric greenhouse gas concentrations, observed warming, positive radiative forcing (see definition at bottom) and improved understanding of the climate system (IPCC Summary Report for Policy Makers, 2013). It has been concluded therefore that athropogenic influences have caused changes to a number of the Earth's systems: sea level rise; spring snow cover retreats; glacier retreats; stratospheric ozone depletion - the list is large.  

'Continued emissions of greenhouse gases will cause further warming and changes in all components of the climate system' (IPCC, 2013). It is therefore vital that we limit climate change in order to not transcend the thresholds that define a safe operating space for humanity with respect for the Earth system (Rockstrom et al., 2009). Rockstrom et al. (2009) identify nine Earth system boundaries and associated thresholds that, if crossed, could cause a dangerous level of environmental change (see below). Their analysis shows that three of the Earth system processes - climate change, nitrogen cycle interference and biodiversity loss - have already crossed their boundaries and the other boundaries aren't far off being crossed either.  

Source: Rockstrom et al., 2009

The seriousness of the issue of environmental change thus goes without saying. Even if emissions were stopped many of the effects of climate change would persist for centuries and a large fraction of climate change resulting from CO2 emissions will be irreversible, unless a large scale removal occurred.  Preventing further change is therefore something that requires substantial and sustained reductions in greenhouse gas emissions (IPCC, 2013). 

The large task at hand thus brings to the fore the methods proposed under the terms geo-engineering and renewable energy. The former of these methods seeks to alter the climate system to counter climate change while the latter provides a source of energy free of greenhouse gas emissions. Can the climate be fixed by either of these? Which, if any offers the better solution?

Lets find out ... 

Definition:

Radiative forcing14 (RF): quantifies the change in energy fluxes caused by changes in Natural and anthropogenic substances and processes for 2011 relative to 1750. Positive RF leads to surface warming, negative RF leads to surface cooling (IPCC 5th Assessment Report, 2013).