編者按
《聯(lián)合國(guó)氣候變化框架公約》第二十七次締約方大會(huì)（COP27）于11月6-18日在埃及沙姆沙伊赫舉行。當(dāng)?shù)貢r(shí)間11月17日下午，氣候過沖委員會(huì)(Climate Overshooting Commission) 在COP27法國(guó)角舉辦了題為”降低溫升可能超過1.5℃的風(fēng)險(xiǎn)“的COP27邊會(huì)。近日，氣候過沖委員會(huì)委員，清華大學(xué)文科資深教授、蘇世民書院院長(zhǎng)、清華大學(xué)全球可持續(xù)發(fā)展研究院院長(zhǎng)薛瀾教授以及氣候過沖委員會(huì)委員、印尼前財(cái)政部長(zhǎng)Muhammad Chatib Basri（穆罕默德·查蒂布·巴斯里）在《南華早報(bào)》發(fā)表觀點(diǎn)文章：1.5 degrees? We need to prepare for a temperature overshoot and worse climate change（《1.5度？我們需要為氣溫過沖和最壞的氣候變化做準(zhǔn)備》），呼吁各方應(yīng)加強(qiáng)行動(dòng)為全球溫升可能超過1.5℃，及其產(chǎn)生的影響做好準(zhǔn)備。以下為文章全文：
As the world’s population reaches8 billion, the consequences of our environmental impact are visible and devastating, from melting glaciers to unprecedented heatwaves and floods. These are set to intensify, in frequency and severity – while countries continue to try to reduce greenhouse gas emissions to limit global warming to 1.5 degrees Celsius above pre-industrial levels.
According to the latest mathematical models and reports from the United Nations and other expert organisations, however, the world is heading for an temperature increase that will overshoot 1.5 degrees, at least temporarily.
Currently, we are on track for an expected warming of2.7 degrees by 2100 – quite simply, too little has been done to cut emissions. What is decided today as a response to global warming will define the climate our children and grandchildren live in.
We need to explore more approaches to minimise the impact of temperature overshoot and reduce its duration. While cutting emissions remains the highest priority, how else can societies adapt to climate impact? Could and should we consider cooling the earth? How do we capture the carbon dioxide released since the industrial revolution?
The first additional approach we need to explore is adaptation to a changed climate. It was high on the COP27 agenda, as negotiators debated gaps in the adaptation funding pivotal to climate-vulnerable low and middle-income countries.
The annual US$100 billion for climate action pledged at COP15 isfar from being delivered. But even this would be insufficient. “International adaptation finance flows to developing countries are 5-10 times below estimated needs and the gap is widening,” said the UN.
Helping vulnerable nations cope with theloss and damage from unavoidable climate change effects is also an increasingly salient matter of equity and social justice. We need to build adaptation programmes with local communities’ ownership and adherence, deliver promised finance and advance the discussion on loss and damage.
The second approach key to reducing the magnitude and length of climate overshoot iscarbon dioxide removal. The UN Intergovernmental Panel on Climate Change concluded that such removal would be unavoidable in scenarios that limit overshoot. These techniques, which are being developed largely in high-income countries, are lacking in developing ones, where nature-based solutions should be enhanced and accelerated by technological additions.
In addition to tech transfers and local capacity development, the full implications of carbon dioxide removal for social, economic and cultural rights, and for the livelihoods of diverse communities and populations need to be fully taken into account.
The last approach, a more debated one, is solar radiation modification (SRM) or what experts call solar geoengineering. This would artificially lower the planet’s temperature, perhaps by mimicking the natural cooling effect of volcanic eruptions. SRM appears able to rapidly and inexpensively reduce global warming, but bears risks, uncertainties and serious governance challenges.
One challenge is that its reportedly low cost and technical feasibility implies that a single country could undertake it, with global spillover effects. The chance of unilateral deployment could be lessened by putting SRM on the international agenda to increase cooperation and collaboration.
Another challenge is that information on SRM effectiveness remains limited and inconclusive, making it a non-viable option. But this research should still be developed as a last resort if and when climate overshoot is unavoidable through emission cuts alone.
Rarely has the world been at such an intersection of issues, with compounding local, regional and global problems. In the face of wars, global health threats and serious economic difficulties, policymakers need to strengthen their response to climate change by choosing the most effective, fair and cost-effective solutions.
The integration of carbon dioxide removal and solar geoengineering into climate-related economic models could provide large economic benefits, in trillions of dollars per year of avoided damage, especially for low- and middle-income countries in warming climates. It is time for governments to assess the benefits, costs and risks of each of these approaches, as they do for every public policy or service provided.
We look forward to accompanying them through our work at the Climate Overshoot Commission, and to supporting them in identifying the best and most cost-effective models to address the likely risk of temperature overshoot.
作者簡(jiǎn)介
Muhamad Chatib Basri（穆罕默德·查蒂布·巴斯里）
氣候過沖委員會(huì)委員、印度尼西亞前財(cái)政部長(zhǎng)
薛瀾
氣候過沖委員會(huì)委員，清華大學(xué)文科資深教授、蘇世民書院院長(zhǎng)、清華大學(xué)全球可持續(xù)發(fā)展研究院院長(zhǎng)
來(lái)源丨南華早報(bào)
供稿丨清華大學(xué)全球可持續(xù)發(fā)展研究院
