As far as climate change is concerned, what impact does it have on human production and life?

How will the entire earth, all parts of the world, and human life be affected by climate change? What we know and don’t know about this issue now. What we don’t know: What will happen in different regions

Even if the average temperature of the earth rises by only 2 degrees, it will still cause some pretty drastic changes. Which places will be transformed into tropical paradises? Which places become damp hells? Which places will become deserts? This is useful to know when planning for the future. Unfortunately, we don't know. The general situation is that the tropics will expand and become wetter; the dry areas at the edges of the tropics will become drier and move toward the pole; and high latitudes will become warmer and wetter. But when it comes to more precise details, it's hard to agree. Some climate modelers even believe that making detailed predictions about Earth's climate change is misleading because, in a way, it means confirming future conditions that don't yet exist.

Our problem is that we don’t know what we are going to do. For example, how much of the Amazon rainforest will be left in 2100? Will this have a significant impact on local rainfall and temperature? This is also a question of climate model analysis. To make calculations manageable, climate models divide the atmosphere into large chunks; making predictions about regional climates amounts to scaling up these models, or using disconnected regional models, using methods that are far from ideal. What's more, Earth's climate models perform poorly when simulating some phenomena that have a major impact on local climate. For example, the Gulf Stream can warm Western Europe, and it is the Atlantic water circulation that forms the Gulf Stream; if this circulation slows down or stops completely, the Southern Hemisphere will become hotter, while northeastern America and Europe will be colder than usual, and the Asian rainy season may Will not start as scheduled. If we fail to properly grasp these changes, our predictions of regional climate change may be wildly wrong.

Oceans expand as they warm. Ice on land melts or slides into the sea, also causing sea levels to rise. If the ice in Greenland and Antarctica melted, sea levels would rise by more than 60 meters. Today we are at the end of a warm ice age. In the past 500,000 years, there have been several relatively warm interglacial periods, when temperatures were less than 1 degree higher than today and sea levels were about 5 meters higher than today. About 3 million years ago, the temperature was one or two degrees higher than the average temperature of the past few thousand years, and the sea level was at least 25 meters higher than it is now. By studying the relationship between temperature and sea level over the past million years, it was found that for every 1 degree increase in temperature, sea level will eventually rise by 20 meters. So, if the temperature rises by 2 degrees, the changes in sea level will be very alarming. As for how vigilant we should be, it depends on how quickly the large ice sheets will melt during climate change - again we don't know.

If the melting of large ice sheets is a slow process that may last thousands of years, then we may still have time to cool the earth before sea levels rise significantly; if the large ice sheets respond quickly to rising temperatures , our descendants may have to live in a new world with dramatically changed coastlines. How much room we have for maneuver remains unclear. The history of past glacier melt doesn't tell us much. Glaciers can melt quickly: North America's ice sheets disappeared during the last ice age; sea levels sometimes rose by more than a meter within a century. Will Greenland's ice sheet melt so quickly? We don't know yet. To accurately predict the rate of sea level rise, we first need to know how hot the Earth will get. As discussed earlier, we don’t know how much the Earth’s temperature will rise; secondly, we don’t know how much additional heat will be transferred to the ice caps. Not long ago, it was thought that the main cause of melting ice caps was warmer air. But now it appears that warmer seawater has begun to play an important role. This is bad news. Warm water accelerates the melting of ice more than air. Warm currents melt floating ice shelves that hold back ice on land. To make matters worse, in some places, like West Antarctica, the land where the ice sheet is located is lower than sea level and will be directly exposed to warm water.

Until recently, the IPCC predicted that as the climate warms, atmospheric moisture increases, and snowfall increases, the Antarctic ice sheet will grow in the 21st century. However, the picture on the ground looks very different. Satellite measurements show that both the Antarctic continent and Greenland are losing significant amounts of ice, and the rate of melting is accelerating. We don’t yet know if this trend will continue, but on current trends sea levels will rise by 0.5 meters by 2100 just from melting ice. Extending this picture globally, many glaciologists now believe sea levels are likely to rise by at least 1 meter by 2100. For some small island countries, this is bad news. Similarly, some cities - such as London, New York and Shanghai, as well as densely populated low-lying areas - such as the Netherlands, Bangladesh and the US state of Florida are also facing crises. The worst-case scenario is that once the glaciers melt, a strong positive feedback effect begins. For example, as ice caps melt, the surface lowers and comes into contact with warmer air. If so, sea level rise will accelerate.

A planet with higher carbon dioxide concentrations and a warmer and wetter climate could support more life if we had enough time to adapt. The problem is that for today's plants, animals, and humans, we have all adapted to an unusually stable climate over the past few thousand years.

Today, the climate is warming rapidly and may be hotter than it has been in millions of years, and we can foresee a future where the climate will become less stable. This is quite a challenge. Many species may have to migrate in order to find an environment with suitable temperatures. To synchronize the availability of food, animals must change the timing of their reproduction and migration. Many species may not be able to. Based on the relatively conservative judgment of the greenhouse effect, theoretical studies have made extreme estimates: about 1/3 or more of terrestrial species will become extinct. Real-world studies of the effects of the greenhouse effect have supported this result. We have also adapted to specific climate conditions, from where we live to our choice of crops. A warming climate, along with an increased risk of major floods and severe droughts, will leave us with more potentially devastating shocks: soaring food prices due to famine, mass migration.

How serious these impacts will be depends on whether we are prepared, such as planting crops that can cope with extreme weather and building corridors outside flood areas for wildlife migration