Economists Weigh In On The Merits Of Net-Zero Climate Goals: Survey

Reuters - Andrea Januta

A growing number of climate economists say the world should take “immediate and drastic action” to tackle climate change, according to a survey.

 A partially submerged car is pictured on a flooded street after Hurricane Florence struck Piney Green, North Carolina, U.S., September 16, 2018. REUTERS/Carlo Allegri

Key Points Failing to tackle climate change could cost the world $1.7 trillion a year by 2050, according to 738 economists. A recent survey shows that three-quarters of economists from around the world strongly agreed that drastic action should be taken immediately. Two-thirds said the costs of investing toward that global goal of net-zero by 2050 would be outweighed by the economic benefits.

Failing to do so could cost the world some $1.7 trillion a year by the middle of this decade, escalating to about $30 trillion a year by 2075, according to estimations by the 738 economists from around the world surveyed by New York University’s Institute for Policy Integrity.

“People joke about how economists can’t agree on most things,” said Derek Sylvan, the institute’s strategy director and one of the authors of the survey. “But we seem to find a pretty strong level of consensus” on the economic importance of climate action.

Three-quarters of respondents strongly agreed that drastic action should be taken immediately, compared with just half of economists polled by the same institute in 2015.

For another question on reaching net-zero emissions by 2050, two-thirds said the costs of investing toward that global goal would be outweighed by the economic benefits, which would include preventing natural disasters, preserving coastal infrastructure and assets and protecting food supplies.

Aerial photo shows damaged and destroyed homes after Hurricane Michael smashed into Florida's northwest coast in Mexico Beach, Florida, U.S., October 12, 2018. REUTERS/Dronebase

To avoid catastrophic climate change, scientists say the world needs to reach net-zero emission by 2050 -- meaning people are adding no more emissions to the atmosphere than they are removing.

Sylvan said he was surprised that so many saw net-zero action as “economically desirable, even on the pretty short timeline that we’re talking about.”

Most of the international climate economists questioned for the survey in February said they had become more concerned about climate change over the last five years. The most common reason they gave was the escalation in recent extreme weather events, which have included climate-linked wildfires and heat waves.

The world saw more than 7,300 major natural disasters between 2000 and 2019, which killed some 1.2 million and cost $3 trillion in damages, according to the U.N. Office on Disaster Risk Reduction. That compares with about 4,200 disasters, leading to 1.19 million killed and $1.6 trillion in losses during the 20 years previous, the data show.

A wind-driven wildfire burns near power line tower in Sylmar, California, U.S., October 10, 2019. REUTERS/Gene Blevins

“Some places are more exposed, and current levels of income matter a great deal,” said Michael Greenstone, an economist at the University of Chicago and the director of the Energy Policy Institute at Chicago.

The fallout from climate change will impact people and nations. 

Economic disparities make it hard to apply simple cost-benefit analyses, he said. For example, a poor family will feel economic losses more acutely than a wealthy family.

“How do we think about a dollar of climate damage to (billionaires) Bill Gates or Jeff Bezos versus a family of four living below the poverty line? I think as a society we have to make a judgment about that.”

Links

• Climate Action Is Expensive, But Inaction Costs Much More, Economists Say 
• Gauging Economic Consensus on Climate Change (pdf)
• Most Economists Agree: Benefits of ‘Drastic’ Climate Action Outweigh Costs of Status Quo
• The Near-Term, Sobering Economic Cost of Climate Change
• Three in Four Economists Agree: Something Needs to Be Done About Climate Change, and Fast
• Economists: Steep CO2 Cuts Are Worth the Cost
• Economists United on Need for Immediate Action on Climate
• ‘Immediate and Drastic.’ The Climate Crisis Is Seriously Spooking Economists

NASA Just Released The First Direct Evidence That Humans Are Causing Climate Change

ZME Science - Tibi Puiu

It was clear humans were warming the planet for some time -- now we have official confirmation. 

A simplified animation of Earth’s planetary energy balance: A planet’s energy budget is balanced between incoming (yellow) and outgoing radiation (red). Credit: NASA.

By now it should be no surprise to learn that the planet is warming very rapidly.
The vast majority of this warming is not natural, over 99% of scientists say, but rather the result of heat-trapping greenhouse gases released by human activity such as burning fossil fuels.

Yet with all the thousands of studies about climate change and its connection with human activity, it was only recently that researchers at NASA have provided direct observations of the driving force of climate change.

Since the Industrial Revolution in the mid-19th century when humans’ appetite for coal and other fossil fuels was first stirred, the concentration of CO2 in the atmosphere has skyrocketed from 280 parts per million (ppm) to over 415 ppm today.

We know beyond a doubt that greenhouse gases such as CO2, methane, or water vapor trap heat in the atmosphere, thereby raising surface temperatures. We also know that CO2 in the atmosphere is increasing at a pace 100 times faster than it should naturally.

At the same time, human activity is also responsible for air pollution, such as particulate matter that we all know is detrimental to our health, as well as that of wildlife. But some of this air pollution is in the form of aerosols, which are minute particles suspended in the atmosphere where they reflect incoming sunlight back into space. In other words, this kind of pollution has a global cooling effect.

Aerosols are thus a force of cooling, whereas greenhouse gases produce heating. The difference between the energy absorbed by the atmosphere, of which greenhouse gases are a major contributing factor, and the energy radiated back to space by factors such as aerosols is known as “radiative forcing”.

When radiative forcing is zero, this means that the planet’s energy system is in balance, so the atmosphere shouldn’t warm nor should it cool.

When radiative forcing is positive, this means that Earth’s system is off balance and warming.

What NASA has done in its recent study is to quantify the individual radiative forcings using satellite observations in order to determine exactly how much each component warms or cools the planet.

LARGE IMAGE

For decades, scientists have devised models of climate change predicting how the temperature will change as a function of greenhouse gases in the atmosphere.

Unsurprisingly, the new NASA study found that radiative forces match these models after it combined data from NASA’s Clouds and the Earth’s Radiant Energy System (CERES), which studies the flow of radiation at the top of Earth’s atmosphere, with other data sources such as ocean heat measurements.

“This is the first calculation of the total radiative forcing of Earth using global observations, accounting for the effects of aerosols and greenhouse gases,” said Ryan Kramer, first author on the paper and a researcher at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and the University of Maryland, Baltimore County. “It’s direct evidence that human activities are causing changes to Earth’s energy budget.”

Another nail in the coffin

Scientists unanimously agree that human activity is the only thing that can explain the steep rise in the average global temperature on Earth, which has increased by a little more than 1° Celsius (2° Fahrenheit) since 1880. Two-thirds of the warming has occurred since 1975, at a rate of roughly 0.15-0.20°C per decade.

Although the evidence for anthropogenic global warming is overwhelming, this was actually the first study to present direct rather than indirect evidence in favor of this explanation for the warming we’re currently experiencing. Up until now, direct evidence that changes in greenhouse gases affect the atmosphere’s ability to transfer heat was only available in localized settings.

According to the study, human activities have caused radiative forcing on Earth to increase by about 0.5 Watts/square meter between 2003 to 2018.

“Creating a direct record of radiative forcing calculated from observations will allow us to evaluate how well climate models can simulate these forcings,” said Gavin Schmidt, director of NASA’s Goddard Institute of Space Studies (GISS) in New York City. “This will allow us to make more confident projections about how the climate will change in the future.”

The findings appeared in the journal Geophysical Research Letters.

Links

• Geophysical Research Letters: Observational evidence of increasing global radiative forcing
• Climate Fight 'Is Undermined By Social Media's Toxic Reports'
• (AU) Lessons From The Past
• Humanity’s Immense Impact On Earth’s Climate And Carbon Cycle
• Causes Of Global Warming: How Scientists Know That Humans Are Responsible
• Blue Acceleration: Our Dash For Ocean Resources Mirrors What We’ve Already Done To The Land
• A Record Share Of Australians Say Humans Cause Climate Change: Poll
• Can Humanity Get Out Of Its Latest ‘Progress Trap’?
• The Great Climate Silence: We Are On The Edge Of The Abyss But We Ignore It
• Humans Causing Climate To Change 170 Times Faster Than Natural Forces

(AU) Mangroves From Space: 30 Years Of Satellite Images Are Helping Us Understand How Climate Change Threatens These Valuable Forests

The Conversation - Nicolás Younes Cárdenas | Karen Joyce | Stefan W Maier

Pixabay, CC BY-SA

Authors Nicolás Younes Cárdenas is Postdoctoral research fellow, James Cook University Karen Joyce is Senior Lecturer - Remote sensing and spatial information, James Cook University Stefan W Maier is Adjunct Research Fellow, James Cook University

Australia is home to around 2% of the world’s mangrove forests and is the fifth most mangrove-forested country on Earth. Mangroves play a crucial role in the ecosystem thanks to the dizzying array of plants, animals and birds they feed, house and protect.

Mangrove forests help protect coastal communities from cyclones and storms by absorbing the brunt of a storm’s energy. They help our fight against climate change by storing vast amounts of carbon that would otherwise be released as greenhouse gases.

In other words, mangroves are some of our most precious ecosystems. Despite their importance, there is much we don’t know about these complex wetland forests. For example, when does their growing season start? And, how long does it last?

Usually, answering these types of questions requires frequent data collection in the field, but that can be costly and time-consuming. An alternative is to use satellite images. In the future, this will allow us to track the impacts of climate change on mangroves and other forests.

Mangroves play a crucial role in the ecosystem thanks to the dizzying array of plants, animals and birds they feed, house and protect. Nicolas Younes

What is phenology?

Our research used satellite images to study the life cycles of mangrove forests in the Northern Territory, Queensland, and New South Wales. We compared the satellite images with field data collected in the 1980s, 1990s and 2000s, and found a surprising degree of variation in mangrove life cycles.

We’re using the phrase life cycle, but the scientific term is “phenology”. Phenology is the study of periodic events in the life cycles of plants and animals. For example, some plants flower and fruit during the spring and summer, and some lose their leaves in autumn and winter.

Phenology is important because when plants are growing, they absorb carbon from the atmosphere and store it in their leaves, trunks, roots, and in the soil. As phenology is often affected by environmental conditions, studying phenology helps us understand how climate change is affecting Australian ecosystems such as mangrove forests.

So how can we learn a lot in a short amount of time about mangrove phenology? That’s where satellite imagery comes in.

How we use satellites to study mangrove phenology

Satellites are an excellent tool to study changes in forest health, area, and phenology. Some satellites have been taking images of Earth for decades, giving us the chance to look back at the state of mangrove forests from 30 years ago or more.

You can think of satellite images much like the photo gallery in your smartphone: you can see many of your family members in a single image, and you can see how everyone grows and “blooms” over time. In the case of mangroves, we can see different regions and species in a single satellite image, and we can use past images to study the life cycles of mangrove forests.

For example, satellite images depicted below, which use data from the Australian government’s National Maps website, show how mangroves forests have changed in the Kimberley region of Western Australia between 1990 and 2019. You can see how the mangrove forest has reduced in some areas, but expanded in others. Overall, this mangrove forest seems to be doing pretty well thanks in large part to the fact this area has a reasonably small human population.

Images: NationalMap/Data61

Our study of satellite images of mangrove forests in the Northern Territory, Queensland, and New South Wales - and how they compared with data collected on the ground - found not all mangroves have the same life cycles.

For instance, many mangrove species grow new leaves only once per year, while other species grow new leaves twice a year. These subtle, but important differences will allow us to track the impacts of climate change on mangroves and other forests.

Satellite images of mangrove forests reveal not all mangroves have the same life cycles. Here we see mangroves at different growth stages. Nicolas Younes

How climate change affects mangrove phenology

Climate change is changing the phenology of many forests, causing them to flower and fruit earlier than expected.

Science cannot yet tell us exactly how mangrove phenology will be affected by climate change but the results could be catastrophic. If mangroves flower or fruit earlier than expected, pollinators such as bats, bees and birds may starve or move to a different forests. Without pollinators, mangroves may not reproduce and can die.

The next step in our research is to figure out how climate change is affecting the life cycles of mangroves. To do this, we will use satellite images of mangroves across Australia and factor in data on temperature and rainfall.

We think rising temperatures are causing longer periods of leaf growth, a theory we plan to test by studying data from now with satellite images from the 80s and 90s.

The next step in our research is to figure out how climate change is affecting the life cycles of mangroves. Shutterstock

Satellite monitoring can’t do it all

Satellites can tell us a lot about how a mangrove forest is faring. For example, satellite images captured a dieback event (depicted below, using data from the Australian government’s National Maps website) that happened between 2015 and 2016, when around 7,400 hectares of mangroves died in the Gulf of Carpentaria due to drought and unusually high air and sea temperatures.

Images: NationalMap/Data61

But satellite monitoring is not enough on its own and cannot capture the detail you can get on the ground. For example, satellites cannot capture the flowering or fruiting of mangroves because flowers are often too small and fruits are often camouflaged. Also, satellites cannot capture what happens under the canopy.

It is also important to recognise the work of researchers on the ground. Ground data allows us to validate or confirm the information we see in satellite images. When we noted some mangrove forests were growing leaves twice per year, we validated this observation with field data, and confirmed with experts in mangrove ecosystems. Field data is crucial to understand the life cycles of ecosystems worldwide and how forests are responding to changes in the climate.

Wetlands, including mangroves, are some of our most precious ecosystems. Shutterstock

Links

• (AU) Australia's Lesser-Known Ecosystems Are Heading For Collapse. Here's What We Stand To Lose
• Bangladesh Coal Plants Threaten World’s Largest Mangrove Forest
• Traditional Owners Urge Climate Change Policy Makers To Witness Mangrove Devastation
• Australia’s Vast Carbon Sink Releasing Millions Of Tonnes Of CO2 Back Into Atmosphere
• Fears Northern Australian Mangrove Forests Could 'Drown' Due To Rising Seas
• Threatened Blue Carbon Ecosystems Store Carbon 40 Times Faster Than Forests
• Mangroves Protect Coastlines, Store Carbon – And Are Expanding With Climate Change
• 'They Died Of Thirst': Extreme Conditions Wipe Out Forest Over 1000 Kilometres