What is the expected investment in capex for Tenaris in 2021 and the following years to achieve the target of a 30% reduction in CO2 intensity
nd gas, maybe by different players, in the U.S. and outside, will be continuing. Maybe the more complex products will be proceeding at a more careful pace.
Frank McGann -- Bank of America -- Analyst
Okay. Does that -- it sounds like you believe then that, that can lead to at least over a period of time or a number of years, a pretty substantial recovery in activity.
Paolo Rocca -- Chairman and Chief Executive Officer
I think that any transition associated with expansion of the world economy will require, let's say, substantial investments in the fossil, oil and gas, especially in the coming years. So this is not a transition that could be done without substantial investment. There are companies that bet on this. There are companies that bet on reducing their exposure. We have to follow this. But in the end, in an aggregate view, I think that there will be recovery in 2022 and beyond. And if the growth in the emerging markets continues, this will need to be substantial.
Frank McGann -- Bank of America -- Analyst
Okay. Thank you very much.
Operator
Thank you. Our next question comes from the line of Alan Spence from Jefferies. Your line is now open.
Alan Spence -- Jefferies -- Analyst
Thanks and good afternoon. I've got two questions, and I'll take them one at a time. The first one is around working capital. You released about $1.6 billion combined in the last two years. Is there any component of this that we should think is structural? Or is it going to be predominantly technical and ultimately, in the next few years come back in?
Paolo Rocca -- Chairman and Chief Executive Officer
If I understand the first question is concerning our working capital. There will be a recovery of working capital because when -- especially in the first quarter and probably because the volume is increasing, and we have to activate some of the longer lead time road will be recovering the working capital need. And then there is, I would say, a second issue that is when we activate Koppel steelmaking in the United States, finishing in United States, these new mills may require and will require some working capital.
On the other side, the introduction of much higher level of digitalization, programming and, let's say, designing of production into the system, there is something that is part of our digital transformation will contribute to a strict discipline in the existing facility. So the combination of these two, in my view, will not bring back Tenaris to the same level of inventory that we had in the past, but we will increase our inventory requirements in the first quarter and to some extent, also in the second quarter, while we are comparing the start-up of the plant.
Alan Spence -- Jefferies -- Analyst
Okay. Thank you. And the second one, on this 30% reduction in CO2 intensity. If I understood correctly from an earlier question, I think you said that could be achieved with your current portfolio of assets. Does that mean that you don't foresee any material increase in capex related to achieving that -- those targets medium term?
Paolo Rocca -- Chairman and Chief Executive Officer
Well, we will have to invest. We are -- as you see, our investment has been reduced in 2020 to around $200 million. Now in 2021, we plan to remain in the range of $200 million of capex, including some of the first in the line investments in energy savings, but including also, let's say, the start-up investment in the translation of the plant of Prudential to Sault Ste. Marie in Canada, the venture in Emirates in each line. So this will be the range of investment for 2021.
Then I think that the decision of capex for the following year will very much depend on the evolution of the market in the second part of 2022. The investment to reach a reduction in our carbon of 30% are let's say, in a period of 3, four years, not, let's say, of an order of magnitude that is strong. We think that we will require in the range of $150 million in the coming four years to reach the target of 30% reduction.
Alan Spence -- Jefferies -- Analyst
Very clear and very helpful. Thank you.
O
nd gas, maybe by different players, in the U.S. and outside, will be continuing. Maybe the more complex products will be proceeding at a more careful pace.
Frank McGann -- Bank of America -- Analyst
Okay. Does that -- it sounds like you believe then that, that can lead to at least over a period of time or a number of years, a pretty substantial recovery in activity.
Paolo Rocca -- Chairman and Chief Executive Officer
I think that any transition associated with expansion of the world economy will require, let's say, substantial investments in the fossil, oil and gas, especially in the coming years. So this is not a transition that could be done without substantial investment. There are companies that bet on this. There are companies that bet on reducing their exposure. We have to follow this. But in the end, in an aggregate view, I think that there will be recovery in 2022 and beyond. And if the growth in the emerging markets continues, this will need to be substantial.
Frank McGann -- Bank of America -- Analyst
Okay. Thank you very much.
Operator
Thank you. Our next question comes from the line of Alan Spence from Jefferies. Your line is now open.
Alan Spence -- Jefferies -- Analyst
Thanks and good afternoon. I've got two questions, and I'll take them one at a time. The first one is around working capital. You released about $1.6 billion combined in the last two years. Is there any component of this that we should think is structural? Or is it going to be predominantly technical and ultimately, in the next few years come back in?
Paolo Rocca -- Chairman and Chief Executive Officer
If I understand the first question is concerning our working capital. There will be a recovery of working capital because when -- especially in the first quarter and probably because the volume is increasing, and we have to activate some of the longer lead time road will be recovering the working capital need. And then there is, I would say, a second issue that is when we activate Koppel steelmaking in the United States, finishing in United States, these new mills may require and will require some working capital.
 On the other side, the introduction of much higher level of digitalization, programming and, let's say, designing of production into the system, there is something that is part of our digital transformation will contribute to a strict discipline in the existing facility. So the combination of these two, in my view, will not bring back Tenaris to the same level of inventory that we had in the past, but we will increase our inventory requirements in the first quarter and to some extent, also in the second quarter, while we are comparing the start-up of the plant.
Alan Spence -- Jefferies -- Analyst
Okay. Thank you. And the second one, on this 30% reduction in CO2 intensity. If I understood correctly from an earlier question, I think you said that could be achieved with your current portfolio of assets. Does that mean that you don't foresee any material increase in capex related to achieving that -- those targets medium term?
Paolo Rocca -- Chairman and Chief Executive Officer
Well, we will have to invest. We are -- as you see, our investment has been reduced in 2020 to around $200 million. Now in 2021, we plan to remain in the range of $200 million of capex, including some of the first in the line investments in energy savings, but including also, let's say, the start-up investment in the translation of the plant of Prudential to Sault Ste. Marie in Canada, the venture in Emirates in each line. So this will be the range of investment for 2021.
Then I think that the decision of capex for the following year will very much depend on the evolution of the market in the second part of 2022. The investment to reach a reduction in our carbon of 30% are let's say, in a period of 3, four years, not, let's say, of an order of magnitude that is strong. We think that we will require in the range of $150 million in the coming four years to reach the target of 30% reduction.
Alan Spence -- Jefferies -- Analyst
Very clear and very helpful. Thank you.
O