10 Reasons to Worry about Climate

ChangePeople, Energy, and the Environment

IPCC Scenarios

10. Rising Sea Levels

9.Glacial, Ice Cap, & Sea Ice Retreat

More than 4 trillion tons of ice from Greenland and Antarctica has melted in the past 20 years and flowed into the oceans, pushing up sea levels 11 mm.

Shepherd et al. (Dec 2012). A Reconciled Estimate of Ice-Sheet Mass Balance. Science.

8. Heat Waves

7. Storms and Floods

6. Droughts

Rising Sea Levels, Melting Ice, Heat Waves, Storms, and Droughts

The U.S. is about to register the warmest year on record in the lower 48 states, and the world its ninth-hottest, a United Nations agency said in a report, adding new urgency to the quest to control global warming.

Two-thirds of the U.S. states suffered drought this year, while heat waves hit across Europe and in Morocco, Jordan, China and Russia, the World Meteorological Organization said in a report released in Doha, where UN climate talks began this week. It noted Arctic sea ice shrank to its smallest on record.

“The alarming rate of its melt this year highlighted the far reaching changes taking place on Earth’s oceans and biosphere,” WMO Secretary-General Michel Jarraud said in a statement. “Climate change is taking place before our eyes and will continue to do so as a result of the concentrations of greenhouse gases in the atmosphere, which have risen constantly and again reached new records.”

Guardian Environmental News Online

5. Disease and PestsClimate change is one factor that appears to be driving at least some of the current bark beetle outbreaks. Temperature influences everything in a bark beetle’s life, from the number of eggs laid by a single female beetle, to the beetles’ ability to disperse to new host trees, to individuals’ over-winter survival and developmental timing. Elevated temperatures associated with climate change, particularly when there are consecutive warm years, can speed up reproductive cycles and reduce cold-induced mortality. Shifts in precipitation patterns and associated drought can also influence bark beetle outbreak dynamics by weakening trees and making them more susceptible to bark beetle attacks.

U.S. Forest Servicehttp://www.fs.fed.us/ccrc/topics/bark-beetles.shtml

4. Economic Disruption

This figure shows the estimated reduction in the U.S. GDP over the period 2010 to 2050 from changes in precipitation, an economically important climatic feature. The values on the solid red line represent the total cost over the 40-year period – placing a 50% probability on the loss of $1.1 trillion – the equivalent of ~7 million jobs. Note how fast the losses accelerate at the lower probabilities. The dashed lines represent the uncertainty of the best-estimate exceedance-probability values. For any given point on the best-estimate line, it is highly likely (.95 statistical probability) that the impact will lie somewhere between the corresponding values on the enveloping dashed lines based on projections with available data.

3. Conflict and War

Antonio Guterres, the UN high commissioner for refugees, told the Guardian: "Climate change is today one of the main drivers of forced displacement, both directly through impact on environment - not allowing people to live any more in the areas where they were traditionally living - and as a trigger of extreme poverty and conflict."

2. Biodiversity Loss“Climate change is likely to lead to some irreversible impacts on biodiversity. There is medium confidence that approximately 20%–30% of species assessed so far are likely to be at increased risk of extinction if increases in global average warming exceed 1.5–2.5 ºC, relative to 1980–99.”

Nobel Lecture by R. K. Pachauri, Chairman of the Intergovernmental Panel on Climate Change (IPCC), Oslo, 10 December 2007.

1. Ecosystem Collapse“As global average temperature exceeds about 3.5 ºC, model projections suggest significant extinctions (40%–70% of species assessed) around the globe. These changes, if they were to occur would have serious effects on the sustainability of several ecosystems and the services they provide to human society.”

Nobel Lecture by R. K. Pachauri, Chairman of the Intergovernmental Panel on Climate Change (IPCC), Oslo, 10 December 2007.

“Localized ecological systems are known to shift abruptly and irreversibly from one state to another when they are forced across critical thresholds. Here we review evidence that the global ecosystem as a whole can react in the same way and is approaching a planetary-scale critical transition as a result of human influence.”

Barnosky, A. et al. Approaching a state shift in Earth’s biosphere. Nature 486, 52–58 (07 June 2012)

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