280 likes | 285 Views
Explore the impact of human activities on climate change, predicting future scenarios based on historical data and global climate models. Learn about greenhouse gas emissions, regional climate changes, and the urgency of addressing this international challenge.
E N D
Modern Global Climate Changeby Thomas R. Karl and Kevin E. Trenberth Summary: Ken Hu Critique: Roy Chen
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.
Main Descriptions • Human influences on climate • The resulting temperature and precipitation change • The time scale of response • Important processes involved • Climate models • Observation and information systems
Human Influences on climate • Global Climate change • Regional Climate change
Global Influences change • Greenhouse gases increase • Aerosols are removed
Greenhouse gases increase • 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 • Half of the increase has been since 1965. • Result(s): global warming
Aerosols are removed • Reason(s): Fuel burning • 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. • Reason(s): Urbanization and agricultural practices. • 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.
Human influence on global climate affects worldwide • Global warning • Surface moisture • Land-surface drying • More atmospheric water vapor
Human influence on global climate affects regionally • Wild fire • Heat stress • Vegetation changes • 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. • Freshwater discharges • Greenland and Antarctica may not be stable Raising sea level
Concepts of the climate system • Climate system is complicated • Three major feedback affect the climate system • Water vapor feedback • Cloud feedback • Ice-albedo feedback
Climate models • 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.
Two atmosphere-ocean system • El Niño • North Atlantic Oscillation (NAO) • El Niño is linked to the global heating • NAO affects the severity of winter temperatures and precipitation in Europe and eastern North America.
Observation and information systems • Simulate the past climate • Comprehensive • Long term climate-related data sets • Observing systems that deliver data free of time-dependent biases • Global monitoring Space-based Surface-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.
Author Credibility Thomas R. Karl • Director of the NOAA National Climatic Data Center, in Asheville, N.C • Fellow of the AMS and the American Geophysical union
Kevin E. Trenberth • Fellow of the American Meteorological Society (AMS) • Fellow of the American Association for Advancement of Science.
Author Opinions: • 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). • We are entering the unknown with our Climate.
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.
Paper Strength • Well developed and organized. • First, authors analyze the some factors cause the climate change. • Greenhouse gases emission and landscape change ( from humans activities directly)
Climate change complicated and amplified by water vapor, cloud, Ice-albedo feedback • NAO and El Niño. ( Ocean current systems) • Second, authors discuss the challenges to analyze uncertainty of climate change. • 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. • U.S did not to produce significant reduction in greenhouse gas emissions, which cause global warming.