EXPLAINER | Climate Change
102 stories

Climate Change

The Svínafellsjökull glacier in Iceland. Glacial retreat is among the most highly visible impacts of climate change. Since the early twentieth century, with few exceptions, glaciers around the world have been retreating at unprecedented rates.

The Svínafellsjökull glacier in Iceland. Glacial retreat is among the most visible impacts of climate change. Since the early twentieth century, with few exceptions, glaciers around the world have been retreating at unprecedented rates.

There is overwhelming scientific evidence that the earth is warming at an unprecedented rate and human activities are the main driver. Global leaders have been meeting for decades to address this issue, which threatens both human and natural systems.

The most recent major effort– the 2015 Paris climate agreement — sought to strengthen the global response and avoid the worst effects of climate change, by limiting a global temperature rise in this century well below 2 degrees Celsius above pre-industrial levels.

A stark United Nations report issued in 2018 calls on governments to do even more– and try to keep the warming below 1.5 Celsius. The scientists who authored it concede that there is “no documented historic precedent” for such a rapid transformation of the global economy, but say the world faces myriad crises as early as 2040—including food shortages, extreme weather, wildfires, and a mass die-off of coral reefs—unless greenhouse gas emissions are sharply cut.

According to the United Nations Intergovernmental Panel on Climate Change, the “human influence on the climate system is clear.” The National Oceanic and Atmospheric Administration writes, “human activities have increased the abundance of heat-trapping gases in the atmosphere, which a large majority of climate scientists agree is the main reason for the 1.5°F (0.85°C) rise in average global temperature since 1880.” Major greenhouse gases emitted by human activities include carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), Hydrofluorocarbons (HFCs), perfluorocarbons(PFCs) ,sulfur hexafluoride(SF6) and nitrogen triflouride (NF3).

Scientists can also look far back into the past and see how the earth’s climate has changed by examining natural time capsules, such as ice cores, layers of glaciers, ocean sediments, tree rings, and coral reefs. Tiny pockets of air left in ice show scientists a “paleoclimate” record, stretching back more than 800,000 years. It reveals “the current climatic warming is occurring much more rapidly than past warming events,” according to NASA’s Earth Observatory.

Although it has a relatively small share of the global population, Pennsylvania is an energy powerhouse and a major contributor of greenhouse gases.

In 2015, Pennsylvania was the third-largest carbon emitter among states, after Texas and California, according to EIA data. Over the past 110 years, Pennsylvania has seen a long-term warming of more than 1 °C (1.8°F), interrupted by a brief cooling period in the mid-20th century, according to the state’s latest climate impact assessment. The state’s warming trend is expected to continue and be coupled with increased precipitation.

 

 

 

Latest stories


The Svínafellsjökull glacier in Iceland. Glacial retreat is among the most visible impacts of climate change. Since the early twentieth century, with few exceptions, glaciers around the world have been retreating at unprecedented rates.

Listen: Climate change and loss of biodiversity

WITF’s Smart Talk features experts discussing climate change and loss of biodiversity

By Marie Cusick

FILE PHOTO:  This combination of October 2017 file photos shows Pennsylvania gubernatorial candidates Democrat Gov. Tom Wolf, left, and Republican Scott Wagner.

Climate change: A crisis for humanity, but not a big deal in the Pa. governor’s race

Neither Gov. Tom Wolf nor his GOP challenger Scott Wagner have made addressing climate change a top priority.

By Marie Cusick

Former New York City Mayor Michael Bloomberg (center) appeared with Pittsburgh’s Chief Resilience Officer Grant Ervin (left) and Pittsburgh Mayor Bill Peduto at West End-Elliott Overlook Park on Sunday.

Methane leaks throughout the entire process of developing natural gas-- from well sites, to storage and processing facilities and pipelines.

DEP moving forward with emission rules for existing oil and gas sources

The rules the DEP is crafting for existing sources will target volatile organic compounds

By Marie Cusick

The Jökulsárlón glacial lagoon in southeastern Iceland.

Can social media actually help curb partisanship around issues like climate change?

New research shows social media platforms can be designed to help people with different political views learn about and discuss complex, controversial topics.

By Marie Cusick

In this July 27, 2018, photo the Dave Johnson coal-fired power plant is silhouetted against the morning sun in Glenrock, Wyo.

New study finds climate change will dramatically alter Earth’s ecosystems

The study showed landscapes across the globe will change dramatically — threatening biodiversity and many natural systems humans rely on.

By Marie Cusick

Homes damaged along the New Jersey Shore after Hurricane Sandy in 2012. (b0jangles via Flickr Creative Commons: https://bit.ly/1mhaR6e)

Study: Sea level rise already hurting coastal real estate prices

Homes exposed to rising seas are selling for about seven percent less than similar properties that aren’t at risk.

By Marie Cusick

The Bruce Mansfield Power Plant burns coal to generate electricity in Beaver County.

Trump administration unveils plan to replace Obama’s signature climate initiative

Although the Trump administration has promised to prop up the nation’s ailing coal industry, it’s unclear how much impact the new rule will have on the economic forces the industry faces.

By Marie Cusick

Lancaster is among the first cities in the world to achieve the new LEED certification for cities.

Lancaster, Pa. among first cities in the world to get LEED certification

LEED, which stands for Leadership in Energy and Environmental Design, has been used to signify green buildings. The certification now includes cities focused on sustainability.

By Marie Cusick

FILE - In this Sept. 15, 2017, file photo, algae floats in the water at the Maumee Bay State Park marina in Lake Erie in Oregon, Ohio.

Study: Climate change hinders summer fun on Lake Erie

In some cases, people waited until later in the day to go swimming, or reported having to head for deeper water to fish. Some people chose to leave the area entirely and not return.

By Marie Cusick
LOAD MORE