Introducing alien ecosystem engineers to Round Island, Mauritius

Species lost – 2 giant tortoises Role – dispersal of herbivore adapted seeds

Surrogate species Aldabra Giant Tortoise Madagascar radiated tortoise

250 kg 16 kg

New topic Climate change and conservation

The main message

Climate

Humans

Biodiversity

Climate change is unequivocal Natural and human systems have been impacted Adaptation and mitigation are necessary Biodiversity/conservation plays a role in

climate regulation Biodiversity/conservation is central to

tackling climate change

Outline for Climate change and conservation

Overview Recent changes to the climate Physical feedback loops Future Climate Change Biological Impacts Ecosystem feedback loops Conservation Implications

Climate shifts are due to change in the retention and distribution of solar energy

Carbon dioxide, methane and water vapour are important in maintaining the current energy balance

Svante Arrhenius (1896) predicted “the emission of CO2 due to the combustion of coal will eventually warm the world”

Air bubbles in ice give

CO2 conc’n of atmosphere at time of ice deposition

Ratio of 18O2 and 16O2 can be used to calculate temperature at time ice is formed

Record dating back 740,000 years

CO2 levels and global temperatures are correlated Current levels (360ppm) are far higher than “natural” levels

CO2 levels and mean global temperature have increased faster since the Industrial Revolution Climate change scientists agree heating is largely due to human induced increases in greenhouse gas concentrations

Changes in temperature over the last 30 years

Changes in precipitation over the last 100 years

Snow, ice and hydrological change

1979

2003

Snow, ice and hydrological change

Glacier National Park – glaciers decline by 70% - gone by 2020

Mount Kenya and Kilimanjaro - decline by 60%

Swiss Alps - decline by 40% since 1850 - gone by 2050?

Grinnell Glacier 1938 1981 1995 2005

Changes in sea level over the last 100 years

Feedback loops

The surface ocean has absorbed nearly half of the increased CO2 levels due to the burning of fossil fuels

The ocean is becoming more acidic 0.1 pH unit since 1750

Continued acidification will reduce the ability of the ocean to take up CO2

Feedback loops

Permafrost soils act as a giant carbon sink approx . 1000 billion tons of Carbon

Warming will thaw the tundra

Melting permafrost will release frozen methane and allow decomposition of frozen plant material

The additional CH4 and CO2 will increase warming

Feedback loops

Warming will melt sea ice and promote growth of shrubs in the arctic

Puddles and shrubs have different albedo (reflectance) than ice and tundra

Puddles and shrubs will warm up rather than reflect UV

Warm puddles and shrubs will increase ice melt and further shrubification

C02 emissions will rise at least until 2040

All scenarios predict C02 levels will continue to rise until the turn of the century

Predicted global temperature and sea levels

What happens if the world warms by 4C?

So

IPCC predicts a rise in temp of 2 to 6.4 C by 2100

Bob Watson (Chair IPCC) the world should “prepare for 4C of warming”

What happened the last time?

55 million years ago Palaeocene-Eocene Thermal Event

5-6C increase

Tropical forests in ice free polar regions Acidified oceans led to vast die-off Sea levels rose 100m higher than todays Desert from South Africa to Europe

What happens if the world warms by 4C?

India Bangladesh Pakistan shorter fierce asian monsoon drought

swUS, Central America, China, South America dried rivers and exhasution of aquifers deglaciation lack of freshwater

Canada/Siberia - reliable precipitation - shelter and food for the world?