世界极大地低估了对气候变化行事的好处。必威官网是真的吗最近的研究from the Global Commission on the Economy and Climate finds that bold climate action could deliver at least $26 trillion in economic benefits through 2030. This groundbreaking research, produced by the Global Commission and more than 200 experts, highlights proof points of the global shift to a low-carbon economy, and identifies ways to accelerate action in five sectors: energy, cities, food and land use, water and industry. Our blog series,The $26 Trillion Opportunity，更详细地探索这些经济机会。

"It's difficult to make predictions, especially about the future," goes a saying variously attributed to Yogi Berra, Mark Twain and Niels Bohr.

Yet, despite the limitations, predictions are essential for policy analysis. Models can cast some light into the darkness ahead, providing the only way to rigorously estimate how policies instituted now will impact the economy in the medium to long-term.

建模在新的气候经济报告中起着关键作用，必威官网是真的吗"Unlocking the Inclusive Growth Story of the 21^st^ Century: Accelerating Climate Action in Urgent Times."Based on a new economic modeling exercise by a team of researchers, including us, the Report found that a shift to a low carbon economy could provide $26 trillion in global economic benefits up to 2030. In 2030, it could also: prevent 700,000 premature deaths; generate 65 million new low-carbon jobs; raise an additional $2.8 trillion in government revenues; and increase female labor force participation

Of course, one needs to be somewhat cautious about all modeling projections. It is difficult to predict the basics of the economy like fuel or commodity prices in the near-term, much less forecast how economies will evolve structurally 15 or 25 years from now, what sectors will dominate, and what technological innovations will fundamentally alter society. But, for the reasons we describe below, the numbers in this Report are actually likely to be低估the benefits of shifting to a low-carbon economy.

We used Cambridge Econometrics' E3ME model for the macroeconomic modeling for this Report, a simulation model originally developed through the European Commission's research framework programs that is now widely used in Europe and beyond for policy assessment, forecasting and research. (Learn more about theE3ME模型).

Here we answer some questions posed to us on the economic modeling.

1.建模是否包括气候变化的影响，例如必威官网是真的吗极端天气事件，例如飓风？

No. The model does not include the impacts of climate change, such as the costs associated with increases in temperature, changes in precipitation patterns and the expected more frequent extreme weather events, such as droughts and severe storms. This is one reason why our study underestimates the economic benefits of climate action: it does not consider the costs of climate change in the baseline, thus overestimating the growth potential if we do not act on climate change. Likewise, the model does not include measures taken to adapt to a warming world.

有一类称为综合评估模型（IAM）的模型，其中包括各个经济领域的气候变化成本，并已用于计算必威官网是真的吗social cost of carbon，，，，the monetary costs associated with emitting climate-warming carbon dioxide (and other greenhouse gases) into the atmosphere. Studies that have employed IAMs generally find that气候不作为的成本远远超过了必威官网是真的吗行动成本，，，，and one criticism of these models (等等）通常，它们通常不包括极端天气事件。

2. 26万亿美元的经济利益意味着什么？

The $26 trillion is the difference in global GDP up to 2030 between our low-carbon policy scenario and the baseline (i.e. absence of new climate policy in the future). To put this in perspective, $26 trillion is about one third of the total GDP generated in 2017.

有两个值得注意的原因是，这一26万亿美元的估计可能是对经济利益的低估。

如上所述，大多数经济基线往往过于乐观，因为它们不包括气候无所作为的成本，例如，遭受更频繁和/或激烈的风暴或某些地区农业生产的损失所造成的损害。必威官网是真的吗费用可能是戏剧性的 - 最新的IPCC特别报告projects global economic damages to be $54 trillion in 2100 with 1.5 °C rise, increasing to $69 trillion with a 2° C above pre-industrial level. Second, climate action scenarios, like ours, tend to be too conservative on technological progress and the potential gains in efficiency in a low-carbon world. They use the best data and assumptions available today, but many ex-post studies of climate and环境政策find that they are both cheaper and easier than was expected, because we can innovate and find new solutions as we start to implement the policies.

3. Why do some other modelling exercises suggest climate action might be costly?

Firstly, some analyses focus only on the initial upfront costs of the low-carbon energy transition, not the long-run net benefits. As noted above, many previous economic studies have ignored the damages associated from climate change. These earlierstudiesthat have estimated little economic effect or a loss of GDP with climate action are comparing a baseline that assumes a) an increase in fossil fuel use without any corresponding economic damages and b) a low-carbon energy scenario where future energy efficiency gains is limited and where renewables are usually assumed to always be more expensive than fossil fuels.

Given their assumptions, it is no surprise that these analyses conclude that climate action is a costly endeavor. But today's reality is that fossil fuel use will cost and is already costing us dearly. Disasters triggered by weather- and climate-related hazards were responsible for thousands of deaths and US$320 billion in losses in 2017. And by 2020, Africa is projected to spend $7-15 billion annually toadapt to climate change，即使将变暖保持在2°C的阈值以下，到2050年的价格也可能达到500亿美元。与此同时，可再生能源的成本继续下降：2010年至2017年之间，the average global cost of utility-scale photovoltaics has fallen 73%. Renewables are already increasingly cheaper that coal or other fossil fuels in many regions today - something few models reflect. Due in large part to this cost-competitiveness, renewables accounted for 70% of new additions to the global power supply in 2017.

Furthermore, our results are in accord with other recent studies. The经合组织，，，，for example, found that climate action can increase long-run GDP by about 5% on average across the G20 countries in 2050 compared to current policies.

4.建模了哪些部门？

尽管该报告描述了需要加速五个关键经济体系（能源，城市，食品和土地利用，水和工业）的结构转型的需求，但模型仅包括能源，城市和行业中的政策行动。如果将必威官网是真的吗气候行动包括在更多部门中，那么经济利益可能会更大。

分析中包括的政策包括：

  • investments in energy efficiency
  • regulation of internal combustion vehicles to promote the uptake of electric vehicles (EV)
  • 燃油税
  • 私营部门的公共购买激励措施投资于电动汽车收费基础设施
  • 碳税
  • removal of fossil fuel subsidies
  • 电力领域的进料关税以促进太阳能和风
  • 各种能源技术的资本投资补贴（碳捕获和存储，生物质和地热技术）
  • 对不同能源技术的调节和循环经济的促进资源效率。

Overall, the combined low-carbon policy scenario results in greenhouse gas reduction of about 50 percent in 2040 compared to the baseline, with most of the reductions coming through the energy reforms and carbon pricing.

5. Does the low-carbon policy scenario reflect the Paris Agreement climate goal?

Yes, our analysis is consistent with the ambition of the Paris Agreement, which calls on Parties to hold the global average temperature to well below 2°C above pre-industrial levels and pursue efforts to limit the temperature increase to 1.5°C above pre-industrial levels (Article 2.1a). Our analysis only covers energy and CO~2~ from industrial processes. If land use and non-CO~2~ emissions--not included in our analysis-- are assumed to follow a pathway that is consistent with Representative Concentration Pathway 2.6 (RCP2.6) of the政府间气候变化面板必威官网是真的吗，我们的低碳政策情况将保持在2°C的峰值温度变化以下，概率大于60％。

6. Are there winners and losers of climate action?

Globally, we will all be much better off under a scenario of bold climate action. But the transition, like any major structural shift, will involve some disruption and dislocation in certain industries, such as fossil fuel extraction. This report underscores the importance of environmentally sustainable economies and societies for all and lays out concrete steps that can be taken to create a just transition for workers and their families. (Those steps and some success stories are总结在这里.)

In terms of countries, those that are net importers of fuels tend to benefit more than other countries in a low-carbon scenario. Likewise, energy-exporting nations tend not to do as well relative to a base case of no climate action, due to reduced demand for the products they specialize in. However, it should be emphasized that it is difficult to anticipate how economies will transition, which we would expect to open up new opportunities as they shift away from fossil fuel-dependent economies. And ensuring that this transition is just and well-managed is essential.

除了能源出口商与进口商之间的分歧之外，我们看到发达国家和发展中国家之间的经济利益几乎没有差异。

Andall与今天相比，各国的GDP将更高。

7.避免死亡的估计值包括什么？

Premature deaths are the adult deaths due to the inhalation of particulate matter (PM2.5) from air pollution. As such, reductions in PM2.5 would come mostly from carbon pricing and energy reforms. The main air pollution-related diseases are lung cancer, chronic obstructive pulmonary disease, ischemic heart disease (from reduced blood supply), and stroke.

E3ME's outputs on air pollution were combined with country-specific data from the International Monetary Fund's study,"Getting the Prices Right"在进气（即，颗粒物量每吨原发性污染物的吸入量）和心血管疾病的死亡率因子上。

If You Know, You Know

因此，尽管我们应该始终对特定数字有所谨慎，但低碳经济的基本轮廓和益处却没有疑问。这项研究增加了一个越来越多的证据，表明低碳世界在经济上以及人类健康，生计和社会包容都有意义。

根据报告的清楚，有一个关键的时间来进行这一转变。在未来两到三年内做出的决定有可能导致未来几年的繁荣未来或锁定污染，不平等和温室气体排放。选择是我们的。