Author: pchan730

There are many different electrical generation methods. Each produces varying quantities of greenhouse gas (GHG) through its lifecycle—construction, operations (including fuel supply activities), and decommissioning. Some generation methods such as coal fired power plants release the majority of GHGs during operations. Others, such as wind power and nuclear power, release the majority of emissions during… Continue reading Carbon footprint of different energy sources—Paul Chan

In many regions of the world, water needed for agriculture and human consumption relies on winter mountain snowpacks. For example, the Sierra Nevada snowpack typically accounts for around 30% of California’s fresh water supply. Yet, there is evidence that climate change is decreasing seasonal mountain snowpacks globally, with potentially catastrophic consequences on water resources. A… Continue reading The impacts of climate change on water resources in the western United States–Paul Chan

According to the National Snow and Ice Data Center (NSIDC), over the past 30 years, the Arctic region has warmed more than any other region on earth due to human-caused climate change. The NASA figure below–an averaged temperature profile from the South Pole to the North Pole–shows that the largest warming is in the northern… Continue reading The role of permafrost in climate change–Paul Chan

A positive feedback is sometimes called a vicious cycle. We all have experienced positive feedback effects. The most common one involves a microphone and a speaker. The electric circuit that connects a microphone to a speaker passes through an electronic amplifier. The amplifier magnifies the signal coming from the speaker and feeds this magnified signal… Continue reading What is a positive feedback? What role does it play in climate?–Paul Chan

On the second day of the Glasgow UN Climate Summit COP 26, a total of 100 countries pledge to halting and reversing deforestation. Why do forests matter to the climate? Land-clearing by humans accounts for almost a quarter of greenhouse gas emissions, largely deriving from deforestation for agricultural products such as palm oil, soy bean,… Continue reading Why do forests matter to the climate? – Paul Chan

Greenhouse effect is the result of greenhouse gases (e.g., CO2, NO2, CH4, H2O, and others) naturally present in the atmosphere. Sunlight (visible light in the electromagnetic spectrum) passes through the atmosphere and warms the Earth’s surface. In turn, the Earth surface radiates some of this energy as infrared (IR) radiation back to space. As IR… Continue reading How do greenhouse gases cause global warming?–Paul Chan

The Earth’s history has gone through many cycles of climate change of much larger magnitude than the change that we are facing today. It then begs the question of why we are so concerned about the present climate change. The answer is obvious. Those earlier climate changes happened before the several thousand years of human… Continue reading Has the Earth’s climate changed in the past?–Paul Chan

Climate change is adversely impacting global ecosystems through its worsening trends and through climate-driven hazards. The range of trends includes creeping atmospheric, land, and ocean temperatures, sea level rise, ocean acidification, deforestation, the loss of biodiversity, desertification, and coastal erosions. Climate-driven hazards include heat waves, wildfires, floods, coastal storms, and droughts. Ecosystems are made up… Continue reading The Nexus between Climate and Ecology—Paul Chan

A week ago, my wife and I had lunch with a neighbor who is a retired real estate broker. This past summer was particularly wet in our part of the country, and many houses in this neighborhood were flooded—some with several feet of water. My neighbor told me that he knew at least half a… Continue reading Climate migrations of the past, present, and future–Paul Chan

Different media outlets do different levels of fact checks. The ones that do thorough fact checks about their writings on climate change include the New Yorker, the Atlantic, ProPublica, the Guardian, New York Times, and Washington Post. They often publish their stories based on new findings from peer-reviewed journal articles. The New Yorker and the… Continue reading Can we trust mainstream media’s climate change reporting?—Paul Chan