科学家模拟小行星碰撞对气候和植物的影响

IBS气候物理中心（ICCP）的研究人员发表在《科学杂志》上的一项新的气候建模研究发表在韩国帕桑国立大学的研究人员，提出了一种新的情况，讲述了我们星球上的气候和生命如何改变，以应对潜在的未来，以应对潜在的未来中型（〜500 m）小行星的罢工。

A new climate modeling study presents a scenario of how climate and life on our planet would change in response to a potential future strike of a medium-sized (~500 m) asteroid.

一项新的气候建模研究提出了一种方案，即我们星球上的气候和生命将如何改变中型（〜500 m）小行星的未来罢工。

The solar system is full of objects with near-Earth orbits. Most of them do not pose any threat to Earth, but some of them have been identified as objects of interest with non-negligible collision probabilities. Among them is the asteroid Bennu with a diameter of about 500 m, which, according to recent studies, has an estimated chance of 1-in-2700 of colliding with Earth in September 2182. This is similar to the probability of flipping a coin 11 times in a row with the same outcome.

太阳系中充满了近地轨道的物体。他们中的大多数不会对地球构成任何威胁，但是其中一些被确定为具有不可忽略的碰撞概率的感兴趣对象。其中包括小行星Bennu，直径约为500 m，根据最近的研究，估计在2182年9月与地球碰撞的机会估计有可能。这类似于翻转硬币11的概率。连续有相同的结果。

To determine the potential impacts of an asteroid strike on our climate system and on terrestrial plants and plankton in the ocean, researchers from the IBS Center for Climate Physics (ICCP) at Pusan National University in South Korea set out to simulate an idealized collision scenario with a medium-sized asteroid using a state-of-the-art climate model. The effect of the collision is represented by a massive injection of several hundred million tons of dust into the upper atmosphere. Unlike previous studies, the new research also simulates terrestrial and marine ecosystems, as well as the complex chemical reactions in the atmosphere.

为了确定小行星罢工对我们气候系统以及海洋陆地植物和浮游生物的潜在影响，韩国Pusan National University IBS气候物理中心（ICCP）的研究人员开始模拟与理想化的碰撞方案使用最先进的气候模型的中型小行星。碰撞的作用是大量注入了几亿吨灰尘到上层大气中的作用。与以前的研究不同，新研究还模拟了陆地和海洋生态系统，以及大气中的复杂化学反应。

Using the IBS supercomputer Aleph, the researchers ran several dust impact scenarios for a Bennu-type asteroid collision with Earth. In response to dust injections of 100–400 million tons, the supercomputer model simulations show dramatic disruptions in climate, atmospheric chemistry, and global photosynthesis in the 3–4 years following the impact (Figure 1).

研究人员使用IBS超级计算机Aleph，为Bennu型小行星与地球碰撞进行了几种尘埃冲击方案。为了响应100-4亿吨的尘埃注射，超级计算机模型模拟显示了影响后的3-4年，气候，大气化学和全球光合作用发生了巨大破坏（图1）。

For the most intense scenario, solar dimming due to dust would cause global surface cooling of up to 4˚C, a reduction of global mean rainfall by 15%, and severe ozone depletion of about 32%. However, regionally, these impacts could be much pronounced.

对于最激烈的情况，由于灰尘而引起的太阳变暗会导致全球表面冷却高达4°C，全球平均降雨量减少15％，而严重的臭氧耗竭约为32％。但是，从区域上讲，这些影响可能很明显。

“The abrupt impact winter would provide unfavorable climate conditions for plants to grow, leading to an initial 20–30% reduction of photosynthesis in terrestrial and marine ecosystems. This would likely cause massive disruptions in global food security,” says Dr. Lan Dai, postdoctoral research fellow at the ICCP and lead author of the study.

“突然的影响冬季将为植物生长提供不利的气候条件，从而导致陆地和海洋生态系统的光合作用最初降低20–30％。 ICCP博士后研究员，研究的主要作者Lan Dai博士说：“这可能会造成全球粮食安全的大规模干扰。”

When the researchers looked into ocean model data from their simulations, they were surprised to find that plankton growth displayed a completely different behaviour. Instead of the rapid reduction and slow two-year-long recovery on land, plankton in the ocean recovered within 6 months and even increased afterwards to levels not even seen under normal climate conditions.

当研究人员从模拟中研究海洋模型数据时，他们惊讶地发现浮游生物的增长表现出完全不同的行为。海洋中的浮游生物在6个月内恢复，甚至在正常的气候条件下甚至没有看到水平，而不是在土地上迅速减少和长达两年的恢复，而是恢复了。

“We were able to track this unexpected response to the iron concentration in the dust,” says Prof. Axel Timmermann, Director of the ICCP and co-author of the study. Iron is a key nutrient for algae, but in some areas, such as the Southern Ocean and the eastern tropical Pacific, its natural abundance is very low.

ICCP主任兼研究合着者Axel Timmermann教授说：“我们能够跟踪对灰尘中铁浓度的意外反应。”铁是藻类的关键营养素，但是在某些地区，例如南大洋和东部热带太平洋地区，其自然丰度非常低。

Depending on the iron content of the asteroid and of the terrestrial material, that is blasted into the stratosphere, the otherwise nutrient-depleted regions can become nutrient-enriched with bioavailable iron, which in turn triggers unprecedented algae blooms. According to the computer simulations, the post-collision increase of marine productivity would be most pronounced for silicate-rich algae—referred to as diatoms. Their blooms would also attract large amounts of zooplankton—small predators, which feed on the diatoms.

根据被爆破到平流层的小行星和陆地材料的铁含量，原本营养不良的区域可能会用可生物利用铁富集营养，从而诱发前所未有的藻类膨胀。根据计算机模拟，对于富含硅酸盐的藻类而言，海洋生产率的爆发后提高将最为明显，以硅酸盐为硅藻。它们的花朵还会吸引大量的浮游动物 - 小捕食者，这些掠食者以硅藻为食。

“The simulated excessive phytoplankton and zooplankton blooms might be a blessing for the biosphere and may help alleviate emerging food insecurity related to the longer-lasting reduction in terrestrial productivity,” adds Dr. Lan Dai.

Lan dai博士补充说：“模拟过多的浮游植物和浮游动物的盛开可能对生物圈来说是一种祝福，可能有助于减轻与陆地生产力降低长期降低有关的新出现的粮食不安全。”

“On average, medium-sized asteroids collide with Earth about every 100–200 thousand years. This means that our early human ancestors may have experienced some of these planet-shifting events before with potential impacts on human evolution and even our own genetic makeup,” says Prof. Timmermann.

“平均而言，中型小行星与地球相撞约100–200千年。这意味着，我们的早期人类祖先可能已经经历了这些星球转变事件中的某些事件，并可能对人类进化甚至我们自己的遗传构成产生影响。” Timmermann教授说。

The new study in Science Advances provides new insights into the climatic and biospheric responses to collisions with near-Earth orbit objects. In the next step the ICCP researchers from South Korea plan to study early human responses to such events in more detail by using agent-based computer models, which simulate individual humans, their life cycles and their search for food.

科学进步的新研究为气候和生物圈对与近地轨道物体的碰撞的反应提供了新的见解。下一步，ICCP的ICCP研究人员计划通过使用基于代理的计算机模型来详细研究对此类事件的早期反应，这些计算机模型模拟了人类，他们的生命周期和寻找食物。