Climate Impacts on Natural Hazards Notes

Climate Impacts on Natural Hazards

Global temperature anomaly from 1991 to 2020 shown on globe mapped with colored pixels.
Last time temperatures were below normal (1976) is highlighted.
Increasing trend in global temperatures post-1996 indicates global warming.
- The coldest temperatures are found in polar regions.
- Northern Canada experiencing a faster rate of temperature increase compared to the global average.

Variability in climate conditions leads to different natural hazards.
Global warming impacts forest conditions, making them more susceptible to fire and infestations:
- Increased heat can dry out forests, weakening trees and making them flammable.
- Drier conditions due to prolonged droughts can lead to more dead trees.
- Weakened trees are more susceptible to pests like spruce budworm.
Not all areas are predicted to become drier; some may experience increased rainfall.
- Climate models show changing moisture dynamics that alter rainfall patterns.

Water's role as a greenhouse gas and its significant impact on climate change:
- More moisture means more rainfall, potentially increasing forest health in some regions.
Oceanic heat pumps (thermohaline circulation) play a vital role in temperature regulation.
Atmosphere circulates moisture from tropics affecting weather patterns.
- Predictive models suggest that both wet and dry conditions may occur in different regions due to global warming.

Global increase in natural hazards has been observed, particularly:
- Number of storms, drought occurrences, floods, and extreme temperatures.
- Each hazard shows a distinct trend; for example, the number of storms from 1980-2011 is rising.
Factors affecting interpretation of hazard trends:
- Improved reporting capabilities, population growth, and changes in land use.

Historical CO2 levels over millions of years show the rapid rise of current levels:
- Current levels above 427 ppm are unprecedented in recent geological history.
Models predicting future climate conditions suggest a significant increase in terms of temperature and CO2 levels if current trends continue.
Significant warming patterns observed since the 1980s with a concerning trajectory.

Projections indicate future temperature increases might approach or exceed two degrees Celsius.
- Extreme temperatures will disproportionately affect the poles and northern land masses.
- Forecasts predict more intense rainfall events, not uniform distribution throughout the year.
Droughts and heat extremities will become more common in many areas, impacting natural ecosystems and human activities.

Geographic regions at risk of natural hazards include:
- Bangladesh and the Philippines have high vulnerability to fatalities from natural disasters.
- Economic costs from natural hazards will heavily impact countries with significant infrastructure like Japan and the US.
- Poor nations will face greater relative impacts compared to wealthier nations in monetary loss.

Climate models must account for complex interactions such as:
- Cloud cover effects and changes in albedo, which can influence solar radiation absorption and global temperatures.
- Increased moisture potentially producing more intense tropical storms or hurricanes.

Climate change introduces unforeseen variability and patterns in natural hazards worldwide:
- There's not a one-size-fits-all prediction; both increased rainfall and drought risks must be understood in context.
Importance of scientific literature and models to inform and adapt to these changing climate impacts effectively.