Human Influence On the 21st Century Climate: One Possible Future for the Atmosphere
New computer modeling work shows that by 2100, if society wants to limit carbon dioxide in the atmosphere to less than 40 percent higher than it is today, the lowest cost option is to use every available means of reducing emissions.

This includes more nuclear and renewable energy, choosing electricity over fossil fuels, reducing emissions through technologies that capture and store carbon dioxide, and even using forests to store carbon.

Researchers from the Joint Global Change Research Institute introduced the work, called the RCP 4.5 scenario, in a special July 29 online issue of the journal Climatic Change. The scenario is one of four that scientists will use worldwide to independently study how the climate might respond to different increases of greenhouse gases and how much of the sun's energy they trap in the atmosphere. It can also be used to study possible ways to slow climate change and adapt to it.

The team used the PNNL Global Change Assessment Model, or GCAM, to generate the scenario. GCAM uses market forces to reach a specified target by allowing global economics to put a price on carbon. And unlike similar models, it includes carbon stored in forests, causing forest acreage to increase -- even as energy systems change to include fuels generated from bioenergy crops and crop waste.

"The RCP 4.5 scenario assumes that action will be taken to limit emissions. Without any action, the emissions, and the heat trapped in the atmosphere, would be much higher, leading to more severe climate change," said lead author Allison Thomson, a scientist at JGCRI, a collaboration between the Department of Energy's Pacific Northwest National Laboratory in Richland, Wash., and the University of Maryland.

"This scenario and the other three produced in this project will provide a common thread for climate change research across many different science communities," Thomson said.

The Forested Future


Five years ago, the Intergovernmental Panel on Climate Change asked the climate science community to provide scenarios of greenhouse gas emissions and land use change to guide computer models that simulate potential changes to Earth's climate.

Researchers decided on four possible targets that span a wide range of possible levels of human-made greenhouse gas emissions over the next century. These future scenarios are currently being used by climate modeling groups worldwide in a coordinated effort to compare models and advance the science of climate projections.

The researchers assigned each of the scenarios a specific target amount of the sun's energy that gets trapped in the atmosphere, a property called radiative forcing. Because of differences between the scenarios, each one will produce slightly different degrees of warming.

The RCP 4.5 scenario shoots for 4.5 Watts per square meters radiative forcing in 2100 and lets economics reveal how to achieve that goal the cheapest way possible. The scenario's 4.5 W/m2 means roughly 525 parts per million carbon dioxide in the atmosphere (currently, it hovers around 390 parts per million). It also means approximately 650 parts per million carbon dioxide-equivalents, which includes greenhouse gases besides carbon dioxide.

Unlike the other three scenarios, RCP 4.5 includes carbon in forests in the carbon market. This affects how people use land, as cutting down forests emits carbon dioxide but expanding forests stores it. An earlier modeling study showed that without placing such a value, forests could get cut down for use as biofuels and the land on which they stood used for crops.

The Greenhouse Race


Starting with the world as it looked in 2005 and setting the endpoint at 2100, the team let the model simulate the greenhouse gas emissions and land use change over the next century. They also ran the model without any explicit greenhouse gas control policy or carbon price to compare how such a future might turn out.

Without any emission controls, carbon dioxide concentrations in the atmosphere doubled by 2100. By design, RCP 4.5 limits them to about 35 percent higher than 2005 levels.

The conditions to limit emissions did not specify how to go about doing that, only that carbon from all sources had economic value. Under limiting conditions, carbon dioxide prices rose steadily until they reached $85 per ton of carbon dioxide by 2100, in 2005 dollars.

In the scenario, the price of carbon stimulated a rise in nuclear power and renewable energy use. Also, it became cheaper to implement technologies that capture and store emissions from fossil- and bio-fuel based electricity than to emit carbon dioxide. Buildings and industry became more energy efficient and used cleaner electricity for their energy needs.

Additionally, carbon dioxide emissions from human-made sources peaked around 2040 at 42 gigatons per year (currently, emissions are at 30 gigatons per year), decreased with about the same speed as they rose, then levelled out after 2080 at around 15 gigatons per year.

Resolving Power

Also, the team converted the results of the scenario to match the resolution of the climate models that are using the results. That way, scientists can more easily integrate RCP 4.5 with climate models. Economies, for example, occur on national scales, but chemical reactions of gas in the air occur in much smaller spaces.

This change in scale to accommodate climate models reveals important regional details. For example, although globally methane emissions change little over the century, their geographic origins shift around. As the century wears on, South America and Africa put out more methane and the industrialized nations less.

In addition, the percentage of people's income that they're spending on food goes down even though food prices rise. The researchers attribute this result to a shift from agricultural practices with high carbon footprints to lower ones, as shown in previous work.

While introducing this scenario to climate researchers, the PNNL researchers provide comparisons to other scenarios with similar emissions limits, as well as to scenarios of the other three radiative forcing targets covered by this community activity. The special issue of Climatic Change features papers documenting those other three scenarios as well as several papers reviewing specific parts of the entire scenario exercise.

"It's very important that the climate community has this resource so that they all work from the same data. This common thread will help researchers and policymakers address the problems that climate change will bring us," said Thomson.

Data and results from RCP 4.5 studies are Open Access and are available from JGCRI's website (
www.globalchange.umd.edu/gcamrcp/)


Source: Science News

Trang trước Trang chủ In ấn
Các bài viết khác ...
» Let’s share knowledge and experience to contribute to disaster risk reduction for the suffered communities! (10-16-2015)
» Let’s share knowledge and experience to contribute to disaster risk reduction for the suffering communities! (10-16-2015)
» A study tour on climate change adaptation models in central Vietnam (06-29-2015)
» Viet Nam needs reform mobility policy to increase climate change resilience, UN (10-21-2014)
» Climate change and air pollution will combine to curb food supplies (08-14-2014)
» NGO role in climate change fight strengthened (02-26-2014)
» Celebrating Tanzania’s Forests On World Environment Day (12-23-2013)
» VN seeks a greener path in face of floods (10-28-2013)
» Coastal flood damage could soar to $1tn a year by 2050 (08-22-2013)
» Adaptability in Agriculture and Forestry Activities in Huong Son Commune, Nam Dong district, Thua Thien Hue province, Vietnam (06-14-2013)
» Model photos of project CBA/VN/SPA/09/004 (01-04-2013)
» Photos of model on rehabilitation of local salt tolerant rice variety (05-10-2012)
» Dialogue on climate change and aquaculture cultivation (04-23-2012)
» Direct air capture of CO2 to fight global warming is too expensive to be feasible (02-13-2012)
» The Arctic is already suffering the effects of a dangerous climate change (02-06-2012)
» Rehabilatation of Local Salt Tolerant Rice Variety in Huong Phong Commune (01-18-2012)
» Model on alternative raising of shrimp, crab and mullet in Huong Phong Commune, Thua Thien Hue Province (01-13-2012)
» Getting adapted to climate changes: both the state and people take actions (01-04-2012)
» CO2 emissions in Vietnam at alarming rate (01-04-2012)
» Hyperwarming climate could turn Earth's poles green (11-25-2011)
 
 
Tiêu điểm
Hoành Bồ phát triển kinh tế gắn với bảo vệ rừng
Gian nan giữ rừng
Lai Châu: Rừng chè cổ thụ 1.000 năm tuổi 1.500m trên đỉnh Khang Su Văn
Nông nghiệp sinh thái không hóa chất: Vườn là rừng, và rừng cũng là vườn
Triển vọng giống lúa chịu mặn
Phát hiện rạn san hô khổng lồ rộng 56.000 km2 ngoài khơi Brazil
Quảng Trị: Nông dân Triệu Phong thích ứng với mô hình sản xuất nông sản sạch.
Sóc Trăng: Chuyển đổi cơ cấu cây ăn trái thích ứng với biến đổi khí hậu
Tài nguyên rừng quý giá: Bảo vệ Trái Đất và con người
Tây Nguyên sử dụng phần lớn giống mới để trồng tái canh cà phê, thích ứng biến đổi khí hậu
CƠ HỘI
Dự án FLEGT khu vực miền Trung tuyển tư vấn cho lớp tập huấn "Phòng cháy chữa cháy cho các thành viên mạng lưới cộng đồng sống phụ thuộc vào rừng"
Dự án FLEGT – Khu vực miền Trung kêu gọi tư vấn lần 2
Cơ hội làm việc với dự án FLEGT – Khu vực miền Trung
Dự án FLEGT khu vực miền Trung cần tuyển tư vấn
Dự án FLEGT đang tuyển nhóm tư vấn thực hiện hoạt động "Thiết lập mạng lưới cộng đống sống phụ thuộc vào rừng" và "Xây dựng mô hình quản lý rừng cộng đồng"
Dự án FLEGT khu vực miền Trung tuyển chuyên gia tư vấn
Hội thảo CÔNG TÁC GIÁM SÁT ĐẦU TƯ CỘNG ĐỒNG TRONG XÂY DỰNG NÔNG THÔN MỚI
KHỞI ĐỘNG QUỸ SÁNG KIẾN “TRẺ EM VÀ THANH NIÊN VỚI BIẾN ĐỔI KHÍ HẬU” GIAI ĐOẠN 2015 – 2016
Đăng nhập
Tài khoản
Mật khẩu
Tin tổng hợp
Việt Nam mới chiếm 6% thị phần thế giới về gỗ và sản phẩm gỗ
Phát huy hiệu quả dịch vụ môi trường rừng
Đề xuất mức chi trả và xác định số tiền chi trả dịch vụ môi trường rừng
Văn kiện hiệp định VPA/FLEGT
Năm 2020 gỗ Việt Nam có thể được cấp phép FLEGT
Chất dẻo sinh học là cách thức bảo vệ môi trường mới ở Nhật Bản
Việt Nam và Liên minh Châu Âu (EU) hoàn tất đàm phán thoả thuận chống khai thác bất hợp pháp và thúc đẩy thương mại gỗ hợp pháp
Phương pháp phát triển cộng đồng dựa vào nội lực (ABCD)
Newsletter
Email của bạn:
Logo các đối tác
 

CORENARM - Trung tâm Nghiên cứu và Tư vấn Quản lý Tài Nguyên

Địa chỉ: 126/14 Nguyễn Phúc Nguyên, Tp. Huế        ĐT: (84-54) 353 9229/3623600

Email: corenarm@gmail.com  Website: http://corenarm.org.vn/

Số lần truy cập: 1480052
Số người đang online: 3