LLL Innis 9 3ALB 2018 CONTEMPORARY CLIMATE CHANGE THE ANTHROPOCENE

Transcription

1 LLL Innis 9 3ALB 2018 CONTEMPORARY CLIMATE CHANGE THE ANTHROPOCENE

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3 Let me remind you that if you want to follow up on anything that we ve covered/not covered, if you need to vent steam, bile, etc., contact me at I ll gladly talk to other groups if you think that would be useful.

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5 Some have proposed that over the last couple of centuries, our influence has created a world with no precedent, and that we should recognize this with a new designation to differentiate it from the rest of the Holocene. The Anthropocene has been suggested. There is no agreement as to when this new age started. A reasonable boundary might be 1850, when the Industrial Revolution really got going, but others suggest 1950.

6 Technically, the Anthropocene is an Epoch of the Quaternary Period (as is the Holocene and the Pleistocene).

7 Some anthropological changes extend through the Holocene.

8 So it s probable that everything we ve done through the Holocene has impacted on global climate. Certainly those impacts have deepened and accelerated in the last two centuries as a consequence of increasing population and technological advances.

9 Ultimately, it s all about technology and population.

10 The changing geography of human distribution and density.

11 If our footprint was just us it would be small.8 billion people could fit inside the blue box to the left a 1.7 km cube.

12 CO2 emissions and population

13 Socio-economic, physical and chemical indicators of the Anthropocene.

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15 How have we modified our planet? 1. the removal and fragmentation of natural habitat. This is not recent and not confined to the tropical rainforest. Deforestation impacts climate locally, regionally and globally. It changes Earth albedo and contributes to the Greenhouse Effect. 2. the creation of new/modified habitats and systems agroecosystems, urban and suburban landscapes, etc. This is reflected directly through temperature and indirectly through hydrologic changes.

16 3. globalization of plants and animals. This is reflected in the loss of biodiversity in both natural and agroecosystems. Loss of biodiversity endangers our ability to feed ourselves and threatens natural global functions. Agricultural systems behave differently from natural systems. In general, they are simple, require huge energy investments (fertilizer, pesticides, etc.). They contribute to global warming mostly through their impacts on GHG production.

17 4. environmental degradation a product of habitat removal and inappropriate land-use (overcultivation and overgrazing, overuse of water and fertilizer, inadequate waste treatment etc.). Desertification, the creation of new deserts, is anthropogenic.

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19 Deforestation of Borneo

20 Deforestation of the US and southern Ontario

21 Tropical forests replaced by oil palm plantations.

22 Natural systems are replaced by agroecosystems

23 Irrigated terraces (left). Dry farming (below). Both in China.

24 Dry farming (left). Plastic forcing vegetables (below).both in southern Spain. From Edward Burtynsky s Anthropocene.

25 Central pivot irrigation. Kansas (below). Jordan (right). Saudi Arabia (bottom right).

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27 Ordos Plateau, northcentral China.

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29 Other landscape modifications. Below are salinas salt evaporation pans near Cadiz, Spain.

30 Extractive industries. Copper mine, Utah (left). Oil in S. California (below left). Oil sands, Alberta (below).

31 More Burtynsky.

32 Urbanization; Currently about 50% of global population lives in cities. That proportion is rising rapidly particularly in developing countries. Big cities generate their own problems of infrastructure (power, water, sewage, food, transport, etc.) as well as contribute to atmospheric chemistry and global warming.

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36 Projected urbanization in China and India

37 5. changes in atmospheric chemistry (acid deposition, ozone depletion, global warming, etc.). Remember that the chemistry and transparency of the atmosphere influences both the receipt, processing and return of solar energy. Any changes in the behaviour of radiation represent positive feedback that will influence the trajectory of global climate in the current situation it induces global warming.

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39 CO2 and temperature. The pace of change accelerated after 1950.

40 The major contributors to global CO2 increases

41 The major culprits by region.

42 Population (left). Per capita CO2 emissions (below).

43 Increases in other greenhouse gasses.

44 The extra CO2 comes primarily from fossil fuel combustion and the removal and burning of forest. Methane (CH4) comes naturally from wetlands. Anthropogenic sources include domesticated livestock, rice paddies and decaying matter in landfills. Nitrous oxide (N2O) comes naturally from microbial processes in soil. Biomass burning is an important anthropogenic contribution.

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46 As we know, a number of things can influence climate change, but GHGs are currently by far the largest contributor.

47 Anthropogenic impacts in the atmosphere do not all lead to warming. Increasing Earth albedo should dampen greenhouse warming as should the large amount of atmospheric aerosol/particulate matter derived from agriculture, industry, transportation, etc.

48 Where does it go from here? Even if we stop all future additions of GHGs, we will not return to pre-industrial levels. The damage is done. The residence time for these gasses may extend at least to centuries unless they are removed and sequestered. The technology is there (as it is for many other beneficial policies), but will we invest the huge expenses required?

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50 Global temperature has increased by only about 1C since 1950 and we are already in big trouble. Most climate change models predict increases from 2C to 5C by The most optimistic predictions suggest stabilization between 2C and 3C if we have a more inclusive and rigorous commitment.

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52 So given that global warming is here to stay, how will it affect our world? How can/will we live with it? We ll take a look next week!