Modern Global Climate Change by Thomas R. Karl and Kevin E. Trenberth Summary: Ken Hu Critique: Roy Chen

Summary

Abstract of the article Abstract of the article The article illustrates the relationship between human influences and modern global climate change. It also predicts the future base on the past information and global climate models. The article illustrates the relationship between human influences and modern global climate change. It also predicts the future base on the past information and global climate models.

Main Descriptions Human influences on climate Human influences on climate The resulting temperature and precipitation change The resulting temperature and precipitation change The time scale of response The time scale of response Important processes involved Important processes involved Climate models Climate models Observation and information systems Observation and information systems

Human Influences on climate Global Climate change Global Climate change Regional Climate change Regional Climate change

Global Influences change Greenhouse gases increase Greenhouse gases increase Aerosols are removed Aerosols are removed

Greenhouse gases increase Reason(s): Burning of fossil fuels and methane and nitrous oxide from multiple human activities. Reason(s): Burning of fossil fuels and methane and nitrous oxide from multiple human activities. For example: Carbon dioxide has increased 31 since preindustrial times For example: Carbon dioxide has increased 31 since preindustrial times Half of the increase has been since Half of the increase has been since Result(s): global warming Result(s): global warming

CO2 and T (Global) VS Time

Aerosols are removed Reason(s): Fuel burning Reason(s): Fuel burning Results(s): Results(s): 1. Either net cooling or net heating 2. Directly reflecting solar radiation and indirectly by changing the reflective properties of clouds and their lifetime

Regional Climate change Changing in landuse. Changing in landuse. Reason(s): Urbanization and agricultural practices. Reason(s): Urbanization and agricultural practices. For example: Large-scale deforestation and desertification in Amazonia and the Sahel For example: Large-scale deforestation and desertification in Amazonia and the Sahel Result(s): “concrete jungle” and its effects on heat retention, runoff, and pollution, resulting in urban heat islands. Result(s): “concrete jungle” and its effects on heat retention, runoff, and pollution, resulting in urban heat islands.

Human influence on global climate affects worldwide Global warning Global warning Surface moisture Surface moisture Land-surface drying Land-surface drying More atmospheric water vapor More atmospheric water vapor

Human influence on global climate affects regionally Wild fire Wild fire Heat stress Heat stress Vegetation changes Vegetation changes Sea level rise Sea level rise

The time scale of response and important processes involved Human-induced climate change is projected to be much faster than most natural processes. Human-induced climate change is projected to be much faster than most natural processes. Freshwater discharges Freshwater discharges Greenland and Antarctica may not be stable Raising sea level Greenland and Antarctica may not be stable Raising sea level

Concepts of the climate system Climate system is complicated Climate system is complicated Three major feedback affect the climate system Three major feedback affect the climate system Water vapor feedback Water vapor feedback Cloud feedback Cloud feedback Ice-albedo feedback Ice-albedo feedback

Climate models The primary tools for predicting future climate The primary tools for predicting future climate Fully coupled, mathematical, computer- base models of physics, chemistry, and biology of the atmosphere, land surface, oceans and cryosphere and their interactions with each other and with the sun and other influences. Fully coupled, mathematical, computer- base models of physics, chemistry, and biology of the atmosphere, land surface, oceans and cryosphere and their interactions with each other and with the sun and other influences.

Example of a modeling the climate system

Two atmosphere-ocean system El Niño El Niño North Atlantic Oscillation (NAO) North Atlantic Oscillation (NAO) El Niño is linked to the global heating El Niño is linked to the global heating NAO affects the severity of winter temperatures and precipitation in Europe and eastern North America. NAO affects the severity of winter temperatures and precipitation in Europe and eastern North America.

Observation and information systems Simulate the past climate Simulate the past climate Comprehensive Comprehensive Long term climate-related data sets Long term climate-related data sets Observing systems that deliver data free of time-dependent biases Observing systems that deliver data free of time-dependent biases Global monitoring Global monitoringSpace-basedSurface-based

Conclusion of the article The article describes that we need better observation and system to project the future global climate change. The climate change is international greatest challenge. The article describes that we need better observation and system to project the future global climate change. The climate change is international greatest challenge.

Critique:

Author Credibility Thomas R. Karl Director of the NOAA National Climatic Data Center, in Asheville, N.C Director of the NOAA National Climatic Data Center, in Asheville, N.C Fellow of the AMS and the American Geophysical union Fellow of the AMS and the American Geophysical union

Kevin E. Trenberth Fellow of the American Meteorological Society (AMS) Fellow of the American Meteorological Society (AMS) Fellow of the American Association for Advancement of Science. Fellow of the American Association for Advancement of Science.

Author Opinions: Climate change is a global issue. Climate change is a global issue. Human activities alter the climate change. For example, global warming effect that results from the burning fossil fuels (energy uses). Human activities alter the climate change. For example, global warming effect that results from the burning fossil fuels (energy uses). We are entering the unknown with our Climate. We are entering the unknown with our Climate.

We need improve climate observing in order to analyze the global climate change. We need improve climate observing in order to analyze the global climate change. Climate change may be our greatest challenge. We should work together to overcome this challenge (global Cooperation and action. Climate change may be our greatest challenge. We should work together to overcome this challenge (global Cooperation and action.

Paper Strength Well developed and organized. Well developed and organized. First, authors analyze the some factors cause the climate change. First, authors analyze the some factors cause the climate change. Greenhouse gases emission and landscape change ( from humans activities directly) Greenhouse gases emission and landscape change ( from humans activities directly)

Climate change complicated and amplified by water vapor, cloud, Ice-albedo feedback Climate change complicated and amplified by water vapor, cloud, Ice-albedo feedback NAO and El Niño. ( Ocean current systems) NAO and El Niño. ( Ocean current systems) Second, authors discuss the challenges to analyze uncertainty of climate change. Second, authors discuss the challenges to analyze uncertainty of climate change. Scientists need to improve observing systems and global simulation model by integrate technologies. Scientists need to improve observing systems and global simulation model by integrate technologies.

Paper weakness Authors did not discuss the efforts to stop global warming effect. For instance, U.N global climate treaty. Authors did not discuss the efforts to stop global warming effect. For instance, U.N global climate treaty. U.S did not to produce significant reduction in greenhouse gas emissions, which cause global warming. U.S did not to produce significant reduction in greenhouse gas emissions, which cause global warming.

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