Rapid climate change is a major topic in contemporary science, in particular, the role of human actions. This period, in which humans have been actively altering the Earth and its systems, is known as ‘THE ANTHROPOCENE’. Current scientific debate whether human activity warrants formal definition as a new phase in Earth history. I ask, has the planet been altered to such an extent as to leave an irreversible mark on the environment?
According to Paul Crutzen Anthropocene means the time since 18th Century, when the increase in burning of fossil fuels released large quantities of carbon dioxide, previously stored within the Earth’s forests, into the atmosphere. This carbon dioxide together with methane and nitrous oxide, accounts for the recent spike in temperatures over the last few centuries.
However, others such as William Ruddiman suggest this time began when humans started farming the land. He argues that Anthropocene began over 8000 years ago, when land clearance for agricultural purposes started the release of CO2 previously trapped within vegetation through activities like slash-and-burn agriculture and livestock grazing. The worry is that these activities will, or have already, led to surpassing of upper planetary ‘thresholds’ which will hinder continued functioning of the earth without negative consequence.
Slash and burn agriculture: beginning the human-induced release of stored carbon over 8000 years ago
So, what is actually happening?
Climate changes naturally in time. The last 2.6 million years, the Quaternary period, was characterised by repeated cool phases, ice ages, with each period followed by warmer conditions. We live in one of these warm intermissions. Increase in temperature is thus not the problem, as this occurs naturally with changes in the Earth’s orbit. The issue is the rate and extent of this increases in temperature.
The most recent assessment report by Intergovernmental Panel on Climate Change’s (IPCC) states that between 1970 and 2010, the shallow oceans have warmed about 0.11oC annually coupled with loss of ice on the Greenland and Antarctic ice sheets, plus ocean acidification. This raises concerns of changing climate as it affects plants, animals, people and places, all of which suffer from accelerated change.
Consequences: Fauna and Flora
Under current warming, extinction of many of the World’s species is imminent. Rates of species loss exhibit numbers high enough to indicate that, today, we may be in the middle of another mass extinction event, with loss of biodiversity occurring at levels much greater than that which would occur under conditions not influenced by human activity. There have been a total of 5 mass extinctions recorded in known Earth history. Mass extinction is defined as an event where a total of ¾ of species are lost. Today, we could be in a human-enhanced 6th event.
When climate changes, animals and plants adjust to changes in habitat altered by temperatures. As this occurs, species respond by shifting from where they live. If these climatic changes occur too quickly, these organisms struggle to adjust at a speed fast enough to survive. These species are pushed into a smaller habitat areas, termed as ‘climatic envelope’. Species in warm areas shift poleward as temperatures near the equator increase. However, where do plants and animals living at the North and South Poles go? The simple answer is, NOWHERE!
One of the more well-known animals likely to disappear as a result of global warming: its choice is adaption or extinction
In 2002 the Larsen B Ice Shelf in Antarctica, collapsed. An area of around 12.5km2 detached from the main ice shelf, which scientists believe to be the result of dramatic retreat of the shelf in recent years. West Antarctica is showing similar instability. Current polar research is focusing on understanding the changes occurring, and how these relate to global warming. If Antarctica alone melts, it will result in about 60m of global sea level rise, enough to cause drastic change all life on Earth.
The Larsen B Ice Shelf collapse in 2002
As much as the IPCC has advocated the need for action, global powers have been slow to respond. Many promote the need for clean energy, sustainable development and appropriate policy making. By 2050 the Earth’s population will be over 10 billion. These people need food, water and housing. We need to rethink our response to climate change, it requires cooperation between disciplines, and universal collaboration. Scientists, policy makers and everyone else should to act on, and deal with, the consequences.
Emma Cooper is a student at Royal Holloway, London University, in her final year.
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