Post on 21-Dec-2015
transcript
Source: IPCC
Source: IPCC
1. Reduced Biodiversity (rapid change)
2. Sea level rise and coastal flooding(melting ice and thermal expansion)
3. Expansion of tropical disease range
4. Soil Moisture Decreases and Desertification ?
5. Increased frequency of heat illness(problem for the elderly)
6. Increased frequency of severe events?
7. Engineering problem of thermokarst(transportation and housing)
8. Affect on outdoor winter recreationand winter tourism
1. Increasing NPP?2. Increased food production?: CO2
fertilization, range & growing season(depends on soil moisture/depth/nutrients)
3. Increased water-use efficiency4. Increased nutrient-use efficiency?5. High latitude warming
(positive and negative)
Source: IPCC
Source: IPCC
Ice core data
Temperature,CO2 and CH4
are all in phase
Are the gasconcentrationsa cause or aneffect of warming or both ?
Source: IPCC
HADCM3 Model Prediction
Global Circulation Model Projection:Non-uniform spatial distribution of global surface temperature increase
Free Air Carbon Dioxide Enrichment (FACE)
FACE Results:
NPP increases(eg. 40% in cotton; 25%for Sweetgum for 550 ppm vs. 370 ppm)
Carbon sink increase limited for forests: Increase in wood production is short-lived; C goes mainly to fine roots and leaves; affected by soil fertility
No effect on LAI
Stomatal conductance decreases (increased water-useefficiency)
Lower leaf nitrogen concentration: need less or have less?
Carbon Sinks
But what are we doing to our sinks ?http://news.bbc.co.uk/2/hi/americas/3609887.stm
Annual Atmospheric Increase 3.3(±0.2) PgC (billion metric tonnes)Why ?
Emissions from fossil fuels +5.5(±0.5) Changes in land use +1.6(±0.7)Oceanic uptake - 2.0(±0.8)
Missing carbon sink - 1.8(±1.2)
Possible source: Underestimation of terrestrial uptakeMid-latitude forest regrowth ?Will the missing sink last ?
Source: Woods Hole Observatory
Source: IPCC
Meanwhile, we are detecting stratospheric cooling !
Why ? Ozone depletionTropospheric [CO2] increases
Interannual climatic variability atthe global scale
Caused by changing atmospheric andoceanic circulation in the tropicalPacific Ocean
Top La Nina December 1998; Middle Normal December 1993; Bottom El Nino Dec 1997
See http://www.cdc.noaa.gov/map/clim/sst_olr/sst_anim.shtml
Q. Is there a relationship between the frequency and/or strength of El Nino Southern Oscillation and climatechange ?
A. We don’t know.
However, effects might be exacerbated in a warmer climate (higher sea levels would enhance flooding, precipitation heavierduring enhancement, evaporation greater during drought phases)
El Nino-related flooding in N. California
Mainly due to shifting winds