Climate Change & People
Not for the first time of late, Bedfordshire has recently experienced a period of exceptionally hot weather while elsewhere in the UK there was flooding.
Thoughts turn to population growth and climate change.
The United Nations estimates that the world population of people is 7.7 billion. In 1950, five years after it was founded, United Nations estimated world population at around 2.6 billion people: it reached 5 billion in 1987 and 6 billion in 1999. In October 2011 the estimate was 7 billion. A global movement "7 Billion Actions" was launched to mark this milestone. The world’s population is expected to increase by 2 billion persons in the next 30 years, from 7.7 billion currently to 9.7 billion in 2050 and could peak at nearly 11 billion around 2100. It is worth noting that (https://en.wikipedia.org/wiki/World_population) in the year 1800 the earth’s estimated human population was 1.0 billion and in 1900 it was 1.7 billion people.
Across the world economic growth trumps every other policy of government with an objective that each year the gross domestic product should be greater than that of the previous year. Perhaps this should now change so the natural environment is brought to the fore with a focus on climate change and how many people Earth is able to support without driving other species to extinction.
There is no doubt about the current impact of the human race on the Earth. All the data below have been taken directly from the websites of the Met Office (https://www.metoffice.gov.uk/weather/climate-change/what-is-climate-changehttps://www.metoffice.gov.uk/weather/climate-change/what-is-climate-change) and and NASA (USA National Aeronautics and Space Administration: https://climate.nasa.gov}.
The UK Met Office says: In the 11,000 years before the Industrial Revolution, the average temperature across the world was stable at around 14°C. The Industrial Revolution began in the mid-1800s when humans began to burn fossil fuels such as coal, oil, and gas for fuel. Burning fossil fuels produces energy, but also releases greenhouse gases such as carbon dioxide, methane, and nitrous monoxide into the air. Over time, large quantities of these gases have built up in the atmosphere. For example, the level of carbon dioxide in the atmosphere rose by 40% during the 20th and 21st century and is now over 400 parts per million (ppm). This level of carbon dioxide is higher than at any time in the past 800,000 years.
The Met Office also provides convincing evidence that the UK average temperature is increasing as displayed below:
This image shows that the five warmest years have all occurred since 2006. Cooler years are blue, while warmer years are red.
In the USA, NASA gives detailed and extensive evidence about climate change on its website. It states that “Scientific evidence for warming of the climate system is unequivocal” (https://climate.nasa.gov/evidence/) and asks the following question: Climate change: how do we know?
This graph, based on the comparison of atmospheric samples contained in ice cores and more recent direct measurements, provides evidence that atmospheric CO2 has increased since the Industrial Revolution. (Credit: Luthi, D., et al.. 2008; Etheridge, D.M., et al. 2010; Vostok ice core data/J.R. Petit et al.; NOAA Mauna Loa CO2 record.)
NASA emphasises that the Earth's climate has changed throughout history: Just in the last 650,000 years there have been seven cycles of glacial advance and retreat, with the abrupt end of the last ice age about 7,000 years ago marking the beginning of the modern climate era — and of human civilization. Most of these climate changes are attributed to very small variations in Earth’s orbit that change the amount of solar energy our planet receives. The current warming trend is of particular significance because most of it is extremely likely (greater than 95 percent probability) to be the result of human activity since the mid-20th century and proceeding at a rate that is unprecedented over decades to millennia (Reference 1). Earth-orbiting satellites and other technological advances have enabled scientists to see the big picture, collecting many different types of information about our planet and its climate on a global scale. This body of data, collected over many years, reveals the signals of a changing climate. The heat-trapping nature of carbon dioxide and other gases was demonstrated in the mid-19th century (Reference 2). Their ability to affect the transfer of infrared energy through the atmosphere is the scientific basis of many instruments flown by NASA. There is no question that increased levels of greenhouse gases must cause the Earth to warm in response. Ice cores drawn from Greenland, Antarctica, and tropical mountain glaciers show that the Earth’s climate responds to changes in greenhouse gas levels. Ancient evidence can also be found in tree rings, ocean sediments, coral reefs, and layers of sedimentary rocks. This ancient, or paleoclimate, evidence reveals that current warming is occurring roughly ten times faster than the average rate of ice-age-recovery warming (Reference 3).
NASA also provides information about the Vital Signs of climate change with respect to Carbon Dioxide, Global Temperature, Arctic Sea-Ice Minimum, Ice Sheets and Sea Level.
For example, Arctic Sea-Ice Minimum (https://climate.nasa.gov/vital-signs/arctic-sea-ice/) indicates that the Arctic sea-ice reaches its minimum each September. September Arctic sea-ice is now declining at a rate of 12.8 percent per decade, relative to the 1981 to 2010 average. The graph below shows the average monthly Arctic sea-ice extent each September since 1979, derived from satellite observations.
AVERAGE SEPTEMBER EXTENT RATE OF CHANGE: Data source: Satellite observations. Credit: /NASA 12.8 % per decade.
The data from NASA satellites, presently circulating the Earth, show the international nature of climate change. Further, the information from the Met Office relating to the UK annual temperature demonstrates the local impact of climate change. Furthermore, the recent increase in atmospheric CO2 levels correlates clearly with the industrial revolution and the exponential growth of the human race.
There is little doubt that Earth and its natural world will survive climate change but the human species may not and, if we do, the consequence will likely be a very different world to the one we now know.
The Covid-19 pandemic has provided an opportunity for many people to consider how they interact with their environments. In England schools will soon welcome back their pupils and as we move towards the end of the lockdown period many of us look forward to the realisation of a new normality.
References
IPCC Fifth Assessment Report, Summary for Policymakers: https://www.ipcc.ch/site/assets/uploads/2018/02/AR5_SYR_FINAL_SPM.pdf
B.D. Santer et.al., “A search for human influences on the thermal structure of the atmosphere,” Nature vol 382, 4 July 1996, 39-46
Gabriele C. Hegerl, “Detecting Greenhouse-Gas-Induced Climate Change with an Optimal Fingerprint Method,” Journal of Climate, v. 9, October 1996, 2281-2306V. Ramaswamy et.al., “Anthropogenic and Natural Influences in the Evolution of Lower Stratospheric Cooling,” Science 311 (24 February 2006), 1138-1141
B.D. Santer et.al., “Contributions of Anthropogenic and Natural Forcing to Recent Tropopause Height Changes,” Science vol. 301 (25 July 2003), 479-483.
In the 1860s, physicist John Tyndall recognized the Earth's natural greenhouse effect and suggested that slight changes in the atmospheric composition could bring about climatic variations. In 1896, a seminal paper by Swedish scientist Svante Arrhenius first predicted that changes in the levels of carbon dioxide in the atmosphere could substantially alter the surface temperature through the greenhouse effect.
National Research Council (NRC), 2006. Surface Temperature Reconstructions For the Last 2,000 Years. National Academy Press, Washington, D.C.